If you can live without all the apps that only exist on Android or iOS, then a non-Android-non-iOS phone is a great choice. But it only takes one of those apps to be essential to you and your non-Android-non-iOS phone suddenly becomes a miserable experience on a daily basis.

You say you don't need a banking app. That's great.

Me, I currently live in a country where banks are entrusted by the government to handle secure authentication online. If you can't use the mobile banking app, you can't interact with social services, the local equivalent of the DMV, healthcare system, police... And you can't book a train ticket, change the trash collection schedule, check if your parcel has arrived at the post office... Everything is online here, and without the banking app, your life becomes very very difficult. Not impossible, but not a pleasant experience.

And my company requires me to use the Teams app. In fairness, if I can't use it on my phone or I refuse to install it on my phone on principles, they will readily provide me with a work phone - and a pretty nice one too. But that means I'll have to carry two phones and, well... I just don't want to do that.

So if a Linux phone works for you, more power to you. It's just that you're a minority of extremely lucky people for whom this arrangement is at all workable.