Why do most modern instant messengers require installation on the phone?

Question

Mobile devices

Take telegrams for example. There is a client for PC, there is a web version. But to register, you need to install the application on your phone.
I myself carry a small laptop to work / study / important meetings. Wifi is everywhere, and where it is not, there are public networks. The need for a smartphone is completely eliminated.
I have a list of IT-related telegram channels that I wanted to subscribe to, but I miss this opportunity.
Why did the authors conceive such a registration condition? What does it give them?

Answer 1

To reduce spam, for example, due to linking to a phone number.

Answer 2

But to register, you need to install the application on your phone.

No need.
You just need to receive SMS. For this, a push-button phone is enough, not a smartphone.
Well, SMS is their way of checking the phone.
Well, the phone is their conditions to identify the account.

Answer 3

Because the developers of commercial messengers focus on the mass user, who is most comfortable with this method, and not on libertarian maniacs, paranoids, those who have no money for a phone, and also on users with marginal requests. And, of course, it is much easier for a phone user to sell something, because the phone already has an application store.

Answer 4

The answer is obvious:
No matter how hundreds of fake accounts are created, they come up with such a clever registration, well, really, only the killer himself will register hundreds of fake accounts in this way