It is a hacked client so best not to use it. I don't know if you'd get a virus (some might, while others not likely, I'm not too familiar with Hacked clients) from it but it isn't recommended due to cheating and other things more so which many servers (not too sure with 2b2t's rules) won't allow you to join if you have one, only users with hacked clients that run servers are the only players your likely to be playing with.
If you have the paid Java Edition just stick with it, if you get signed up for 2b2t congrats, otherwise not much else I can say really.
No, you won't get a virus, it's not because it says that it's dangerous that it actually is. And when you've installed impact, make sure to only turn on allowed hacks or you will be kicked. So don't try flying or something, it won't work. But you probably knew that already. Succes on 2b2t!