With Telegram I can see at least appeal in using it as news source, chat room or for bots, but what offers Signal besides hype about The Current Thing?
Signal uses centralized server with closed source (they hidden code for one year until they finally gave up when users nagged them, nobody knows what they did during that year), Signal requires your phone number, Signal doesn't allow third party apps officially and tried to push some shady crypto, I mean how many red flags you need to avoid such POS app?