When Twitter first started, people also wanted edits and longer messages, yet arguably it took off because of limitations not despite of them.
If Amethyst ends up being the preferred client of 5% of all users and fails to convince others to adopt editing, those users will assume they can edit as in fact they do, yet 95% of their followers only ever see the unedited version. This causes confusion and I think if other devs remain reluctant to adopt editing notes, retiring this feature should be an option.