The main benefit seems to be that to read your messages code has to be send to your browser. That is much easier to detect compared to compromise of the server now.
Plus it would have network effects that would benefit normal users.
In theory you could have clients with good guis and all that, these however barly exist and people simply want to use the web for this sort of stuff.
If your answer to solving a issue that billions of people deal with, then "Don't" is just not the solution expet maybe if there is a feature complete replacement.
Sending code to a desktop is easy to detect. Sending code to a non-web-based mobile app is easy to detect. Sending code to a browser isn't even detectable. In practice, no one audits JavaScript. If browsers offered the means to detect changes to cached content, security experts[1][2][3] would be less grim about webpage security.
Encryption done in untrusted JavaScript is security theater. If these websites offered privacy policies claiming to never read your data, like Riseup does, the end-result would be the same. Safer, actually, because deploying unnecessary crypto increases the vulnerability risks.
Recommending these websites is actively dangerous. Journalists and whistleblowers who take these claims of fraudulent security seriously, are going to be killed. Getting them to understand that email cannot be secured in-browser, is the entire point. That if you have important information to protect, you should be moving onto different approaches.
WhatsApp is literally safer than this, and it's more accessible.
The main benefit seems to be that to read your messages code has to be send to your browser. That is much easier to detect compared to compromise of the server now.
Plus it would have network effects that would benefit normal users.
In theory you could have clients with good guis and all that, these however barly exist and people simply want to use the web for this sort of stuff.
If your answer to solving a issue that billions of people deal with, then "Don't" is just not the solution expet maybe if there is a feature complete replacement.