For one thing, it still has the option for an additional fingerprint lock to open the app.
Sure, my phone itself is locked anyway, usually.
I still like having the second lock built into the app itself for the odd time (however rare) that I hand my unlocked phone to someone.
I know they're not snooping into my signal messages while I blink or misclick on a notification or whatever.

It may not be a big deal for some/most but I like that feature and I can't imagine that's something that needs much upkeep once initially implemented.

I'm sure it's not the only feature, but it's one I use often.

Molly has more features and it's developed by indie devs.