I have both on a couple of devices, not a massive difference between, IMO. It feels like more people uses gram so possibly a larger target audience.
Discussion
The difference is no e2e encryption in telegram groups. Why using anything like that when other better solutions are available?
The history shows telegram leaks when telegram operator decides to disclose them. (It is encrypted on their servers, they have keys)…🤷🏼♂️
I understand larger target audience which for “shillers” is the most important argument.
But anyway sounds like a bad deal to me from privacy perspective.