i havent really thought about that aspect really. would social logins (including: twitter, github, maybe reddit) help? or would you rather see some registration process so passive you dont even notice? (like you start with creating the phrase and i ask for email anyway, why not send you a random pw then).
i cant do this userless as i am pretty sure this is against several anti spam restrictions.
also you are clearly part of the 10% that know why. most installations ive seen did not use the whitelist approach and assumedbit ships with a good blacklist.
btw: chrome unloads tabs. especially pinned ones seem to be WAY less ram heavy when unused. i dont know about firefox tho.