I’ve been using 1Password every day for over 11 years now. The oldest passwords I’ve got stored are for Twitter and Dropbox (yes, the passwords have been changed but the records were first created in 2009). It’s one of those apps which has been made with proper craftsmanship and care, so while I’m not a Linux user, I’d have no problem recommending based solely on Agilebit’s reputation.
But why a whole electron app just to store passwords?
Linux doesn't have a standard desktop environment or widget toolkit. Electron doesn't seem like a worse choice than the other options, and it's easy to find engineers who know how to work with it.
1Password doesn't just store passwords. It has a bunch of other features. It's a fairly complex app at this point. It also has fairly similar user experiences in Windows, macOS, Linux, iOS, and Android, and that's pretty hard to pull off. If Electron helps them accomplish that, that's fine.