Scale. Telegram has 50m users that use it seriously and all of them also use other messaging. Whatsapp has 1-2 billion, and for a majority of them it is their main or only messaging application.

20x larger scale means 20x more clout to bribe/lobby lawmakers and to get around the KYC/AML rules that are the main obstacle in these sorts of things.

The other major difference is their use of Paxos USD, a stablecoin that's tied to the dollar.