Yes but that's because the server has access to all your messages, they are not end to end encrypted.

It makes things a lot easier yes but you do give up a lot of privacy too.

The server, and plausibly at least one secret service. Telegram datacenters are located in Florida, Amsterdam and Singapure.. guess local jurisdiction applies.

I am 100% convinced that whatsapp has backdoors and so I might as well just use the convenient one.