Not for most people. You definitely did not need it for making an app for your mom. I've released games under my own name and never did that.

A random person releasing an app or game on the App Store - you won't need it.

But on Android you still might, even for something small, since they changed the rules for new developers. As of November 2023, any new developer account releasing an app basically has to have an Organization account to publish.

Otherwise, the only way to do it as a solo dev is to go through some arduous testing phase with Google, where you have to find 12 or more people to help test at certain times for 14 consecutive days. If even 1 tester doesn't show up or deletes the app, it resets. Comical, but it's how they lowkey force you to create an Organization.

And people should form companies (and operate as Organizations on platforms). It will protect you in the long run, and you can pay lower taxes on revenues. The main problem I have with it - and this also goes for certain payment processors - sometimes I just want to try an idea. Or like your example, build an app for a friend or relative without a ton of hoops to jump through. Involving a 3rd party credit bureau that operates as a private company - that apparently sells people's data to shit ball marketers, doing whatever else they want with basically no oversight - seems in almost all cases overkill and whack as a process as big as Apple or Google app submission that is borderline a public service if you're willing to not pretend we don't have 2 main choices in this market.

The app store platform should just forward on to the downloading user that it's a corporation in Delaware, or whatever. They kinda do - with the "copyright" field, but that field and value has no legal bearing on anything and can be changed without a review - where even being an individual or "sole" proprietor is a legal designation. You could still form a company under your own name later. Adding a business license should be some optional thing IMO that links through to a local registry if possible and if not, then the end user can deduce that it is not "verified" to be that entity.