Networking can be a confusing subject, and the various security and setup considerations that depend on the type of network and whether you're using a public or private IP address only add to the confusion. While your home router is connected to the Internet, it gets a public IP address from your ISP so the Internet knows how to route data back to your home. This is usually a dynamic IP; that is, it changes occasionally as your ISP reconfigures its network. Businesses and those who host servers often pay for a static IP from their ISP so it never changes, but that's not really necessary for most users these days. Additionally, a dynamic, publicly accessible IP address is more secure, easier to configure, and saves money.
3 More safety awareness
Dynamic IP addresses reduce tracking and attacks
Publicly accessible dynamic IPs are superior to static IPs for most internet users. They're easier to set up and manage (since you don't have to do anything) and offer a number of security benefits you'll appreciate. Note that we're not talking about IP addresses used on your home network behind your router here, just the IP address you generally see on the internet and assigned to you by your internet provider. Having a dynamic IP shown to the world helps with security because hackers are often looking for static IP addresses to focus on. If your IP changes frequently, the target you present to the world is smaller. It's not outright gone, but it's definitely smaller and every little reduction helps.
This reduces the temptation and opportunity for hackers to track you, but also reduces the likelihood of targeted IP-based cyberattacks. These may not be hacking, but other inconveniences like DDoS attacks that can disconnect you from the internet for their duration. I've been attacked this way before by hackers who found out my public IP address via IRC and knocked me offline for a day or so at a time until the ISP changed my public IP address back. This is not fun, and these days most messaging platforms hide your public IP address, making these attacks harder to pull off. Dynamic IPs also reduce tracking for other reasons, like advertising.
2 Dynamic DNS is superior for hosting
Don't pay your ISP for a static IP
One reason for using a public static IP address might be that you want to host servers, for example one that Minecraft for you and your friends as a private space. But have you considered the security and privacy implications? Companies with publicly accessible static IP addresses pay large sums to companies like Cloudflare to provide DDoS protection, among other security tools, to prevent the servers from being taken offline by bored hackers or script kiddies.
Instead, you can sign up with a dynamic DNS (DDNS or DynDNS) provider. These services act as a middleman, constantly mapping a hostname to the changing public IP address your ISP assigns. Then, instead of pointing web services to your public IP, you use the hostname, which is more secure, easier to remember, and often significantly cheaper than paying for a static IP and the necessary security tools. Some routers also have their own DynDNS services, which are either free to use, like Asus devices, or part of a subscription, like Eero routers.
1 UPnP and NAT take care of the complicated parts
No manual port forwarding or manual assignment of IP pairs required
In the early days of the Internet, every device had a public IP address and could be addressed directly by games, servers, and other services. This wasn't a problem back then because the number of devices was smaller than the number of available IPv4 addresses. However, with the explosion in the number of Internet-connected devices, this has become a major problem. To solve this problem, Network Address Translation (NAT) was invented, which allows devices on your home network to communicate with the Internet without running out of IPv4 addresses. With NAT, it looks to the devices on the Internet that they're communicating with as if all of your home devices have a static IP.
Likewise, applications and services on the Internet use specific ports to enter and leave your home. You can think of them as little doors at the end of tunnels, if that helps visualize it. This used to have to be set up manually until UPnP came along, which automatically forwarded these ports to the devices and services that needed them. Modern services and games use UPnP, so the user doesn't have to worry about manual port forwarding, and you still don't need a static IP address to use it.
You probably don't need a static IP address
So, aside from the security benefits, resilience against tracking for advertising and other purposes, and technologies like Dynamic DNS and UPnP that make static IP addresses unnecessary at the consumer level, are there any reasons you'd want one? If you're using it on your home network, of course. This will give you consistent, reliable connections to individual devices, such as a home media server, so other devices on your network know how to reach them. But you still shouldn't set a static IP on the device. Set it as a reserved IP address for that device in your router's DHCP settings. That way, DHCP will always assign it the same IP address without causing any problems, like two devices getting the same IP address.