What is your definition of unusable in the context of UX? When the signing confirmation modal of the extension pops up randomly without any interaction logic / user input?
Discussion
For android any signing request will switch the app over to amber, so if one signing request pops up its not bad. but when there are 5+ in a row it becomes unusable. in the worst case it never ends
For web the signer takes focus away from the window, so its annoying but sometime manageable if I ignore some of the signing requests
💯
What often bother me (and is maybe even worse) that if I decline a signing request, often nothing happens or things are just freezed.
"What's the point of having cryptographic signatures if I can only uses them in "sign everything" mode?"
With asking this question, you also state / assume that the user will fully distrust the client? Which is a good and fair point to start with imo :) but over time, your client could gain trust