Do we need registration on onehash ? Or can we bet on matches without having to create an account there ?
You have the choice to register but you can also bet without registration. Try it and visit for example the basketball games today on https://www.onehash.com/category/sport/basketball/.Put your receiving address so that if your bet will win, the winning amount will be transferred there. And after inputing your receiving address, there will be a generated bitcoin address where you need to send bitcoin as your bet.
Anyway, i would like to tell OP if it would be better to create an account/sign up on onehash since it's very simple and also you will earn some advantages after you signed up/created an account on there. The advantages are, you can earn some rain through their chat box if you always active on there, and you can earn some extra bitcoin after you make people joined under your affiliate link (after you've signed up).