IMO, Design Patterns are mis-named. I rarely see the pattern when I design something. It's usually only after I'm working on something for a while that I see the pattern, then I refactor.
Design Patterns are a standard way to define how something works. If I say "the app uses MVVM", then other devs know how that part of the app works.
By using patterns, you will create better, more maintainable software. But beware, patterns can also be overused and make the code harder to understand.
