I agree that I often want a human involved in room selection, but you can still sanity check your choice by going to the front desk to check in when you arrive (or call ahead).

That said, I have found it useful to grab a more preferable room for obvious things. For example, when staying at the Conrad DC I used the app to choose a room on a higher floor that wasn't facing the main road that I thought might be noisy. It was nice to do this easily in app, because I was checking in late and was concerned room choice would be more limited when I arrived. I think it just let me choose the morning of arrival, I'm guessing a human made decisions to give loyalists preferable rooms and upgrades before giving lowly golds like me access to choose.