Yeah... the signing extension via cashu.me works great on desktop. I don't believe it's available for mobile, though (at least not iOS anyway). It think "dangerous and not recommended" could be an exaggeration - but I think that depends on how secure you wish to keep your nsec. Personally, at this time, I consider my nsec/npub disposable, but I still try to practice good nsec hygiene by sharing it no more than is absolutely necessary.