Hello!

I bought the non-Steam BDO some time ago, now its 'free' on Steam so I just clicked and added to my Library.

Should I convert my non-Steam version into Steam version, is it even possible and how to do it, and are there any benefits or drawback of having Steam vs Non-Steam versions?

Thanks in advance!

Its not possible unfortunately two different clients :/ even if they are the same server . Steam as transaction fees hence how they make their money so PA probably is prefering customers on their client version

Yeah steam not allow such things.