On Telegram it works fine for me.
It saves you the trouble of opening two apps. Nothing more.
We should have telegram style bridge that let's you talk to WhatsApp accounts without having an account in WhatsApp.
Maybe EU DMA will do it? I don't know
I use the Element One subscription, with bridges to Signal and WhatsApp.
It enables a bit more than "not having to open two apps" (although that in itself is nice). It means that I have one, good, client on any platform I want and it has all the messaging. I don't have to double up the client on every platform I want to read/write messages on.
Plus, I get a proper backup of all my messages without having to worry about how that happens on WhatsApp and Signal (the Signal situation is a bit complicated here).
That seems like a strange statement to preface with "IMO".