You've been able to select your room for far longer than two years. I remember at least five years ago, and this press release suggests it was a decade ago. Though it used to be online, before Hilton got the app (I still usually do it on their website rather than app).That's been a relatively new add to the Hilton app (maybe last 2 years or so) -- it's really great, but it also depends on your arrival time. If you show up early, it's possible that particular room had a late check out and isn't ready, yet.
https://hospitalitytech.com/hilton-... Garden Inn, Homewood Suites and Home2 Suites.