I agree that Hinative isn’t quite the same, I’ve been using the HelloTalk app which has a Moments feature – the diary entry can fit into that… But HelloTalk is much more messenger focused, and I’m too slow to really enjoy messaging native speakers directly. I feel pretty bad not responding much, but it’s deeply exhausting. :P
tl;dr: it would be really nice to be able to get a lang-8 account!