Honestly I ask this question a lot, but without a passive-aggressive intention. I just don't understand everything and I hope the asked person can explain it to me well enough, that I understand why.

It's usually really helpful for both.

I think that's fair as consumers will certainly pose the same question.

"Couldn't you just put a text file in Dropbox instead of use a todo app / password manager?"

"Couldn't you just rent a server instead of Amazon's?"