Ethereum offers smart contracts but it's not like it can't do 'real payments'. Thus, it is rather an advantage of it rather than disadvantage. A big problem with eth (even though I think it nevertheless is a step forward after bitcoin) is that it has problems with code's safety. Somehow most of bugs and money losses due to hacks occur with ethereum. This has to be changed, of course. Nevertheless, I think bitcoin will always be the choice #1. Not because it is better than eth but 'cause people tend to choose the most popular so far. There are much more opportunities with btc than eth and lots of people ignore all other coins.