Young perverts, what is the advantage?
What advantages it has over a regular phone: that’s obvious.
Plain regular phone messages aren’t fully encrypted and operators keep logs on their servers for quite a long time (according to local policies, federal and provincial rules). Even if it’s a burner phone, logs will store triangulation data, and by correlating nearby IMEIs you can identify with 99% accuracy which other phone (yours) is travelling with your burner.
So any messenger is already better than a regular phone for privacy.
Messages in
Telegram ARE ALSO NOT ENCRYPTED by default. Although an encryption option exists, it’s optional and practically nobody uses it. Unlike SMS on a phone, these messages are stored on Telegram’s servers, which might ignore requests from Canada and refuse to hand over your chat. But that’s an illusion, since Telegram will hand over your data just like WhatsApp would if the request is properly issued.
For an ordinary person, using WhatsApp or Telegram is basically the same. Both let you set message deletion timers and make messages self-destruct.
Telegram does have a very convenient feature -- self-destructing photos: an SP can send to a pooner her photo and it will disappear as soon as he views it. It’s not 100% reliable, but it’s better than casually sending pictures to anyone.
If you’re high-profile, the choice between WhatsApp and Telegram depends on the threat model. For high-profile users neither option is suitable; the methods that are suitable lose on usability and popularity.
Regarding service providers:
If she’s a foreign student or tourist, a law could be passed at some point (in the feature) allowing border officers to access her text history, and then she might be denied entry for having worked illegally. Messengers is better.
Not safer for work, but better for privacy.
For SP who already have citizenship/PR and can’t be turned away at the border, an ordinary phone is actually the better choice: she may feel safer, because clients who text from regular phones already provide partial ID. This applies only to those who work independently. For those who work through an handler, it depends on the handler's priorities.
Telegram is popular because of its marketing. It’s promoted as abuse‑resistant, very private, and user‑protecting -- but that’s just a gimmick people believe.