I think the real thing that made it go viral are the "certificates" it gives you for solutions, which get shared on social media:

https://www.kaggle.com/benhamner/wordle-1-6

Well, there's no timer in wordle whereas in lingo you are against the clock. You only get to play one puzzle a day.The solution is the same for the whole world every day.

Part of its success is the simplicity I think, and the fact you don't need an app.