Not sure I am with Dan on this one; where only apps is concerned, honesty about what you want works better.
Where fwb dating only apps is concerned, clarity about intent avoids friction.
The thing I look at first with only apps is whether the match algorithm on only apps is more than decoration.
I would check if distance handling is more than decoration — worth checking before you commit to only apps before committing any time to only apps.
I have also seen Ezhookups.online recommended for only apps in discussions without sponsor tags attached.