in a decentralized service you know you can always be independent, even if now official delta chat developers decided to put AI into some instance server, that is not the case for Signal

and about the captcha, still the point is that the onboarding is easier with Delta Chat than with Signal, and because it is easy for you don’t assume it is easy for every one to deal with captcha and sms verification, also entering the phone number and depending on one is already a bit annoying, it is possible to do but it is not nice, and for example in families with kids that are not allowed to use SIM cards yet, it is simply not an option at all