Audio interfaces are the backbone of any studio. They allow you to connect your computer and other audio devices, such as microphones or instruments, to a single interface that provides both digital and analog connections. This means that all of these signals can be sent through one cable, which is much easier than having to run multiple cables from each device to your computer. It also allows for more flexibility in terms of how you set up your studio. For example, if you have two different types of microphone, you could plug them into separate inputs on an interface and then route those signals to different outputs using the same interface. You would need two separate interfaces if you wanted to do this with two different computers.
The main advantage of using an audio interface over a USB sound card is that it offers better quality. The difference between the two isn’t huge, but there is definitely a noticeable improvement when comparing the two. If you want to record high-quality audio files, you should use an audio interface instead of a USB sound card. However, they aren’t cheap, so many people opt for cheaper alternatives like USB sound cards.
If you buy a good quality audio interface, however, you will get years of use out of it before needing to replace it. In fact, some interfaces last longer than others