It was compelling and original when the concept didn't exist, or at least hadn't been successfully brought to market like they did. In a world where Twitter exists, and has the network, there is nothing compelling about a Twitter clone.
None of these platforms started with a network. They weren't cooked up by evil investors and MBAs looking for a rent-extraction scheme. Nor were they designed by a committee of philosophical experts saying "oh we'll just copy their thing and make it more esoteric and confusing so that maybe one day we can aggregate content from 14 competing Twitter-like platforms and you can switch between them whenever you like!" They were started largely by kids goofing around and making fun things for people.
None of these platforms started with a network. They weren't cooked up by evil investors and MBAs looking for a rent-extraction scheme. Nor were they designed by a committee of philosophical experts saying "oh we'll just copy their thing and make it more esoteric and confusing so that maybe one day we can aggregate content from 14 competing Twitter-like platforms and you can switch between them whenever you like!" They were started largely by kids goofing around and making fun things for people.