I wouldn't consider being in a relationship with someone if I wasn't attracted to them. If I'm choosing between the ugly person and the beautiful person, I'm going to assume in this scenario that I'm attracted to the both of them. I'm also going to assume the ugly person is someone that's defined by society to be less attractive, in which case, they'd be unconventionally attractive to me and have quirks about their face that make them stand out - which is the kind of physical features that I tend to like.
The only reason I would want to be in a relationship with someone is because I'm interested in continuing my life with them. If I was considering a relationship with two people - one online and one off, I'd choose the offline one. I've had an online relationship and while I still really care about that person and talk to them regularly, the relationship itself wasn't very good and became way too difficult to uphold.
Eventually you're going to have to meet the person if you choose online if you want to really be with them, and that's a risk in it's own because you don't know if it's going to work out like you hoped it would. Even though there are relationships online that work out (like Drummershuff's!), a lot of them don't. The challenges that come with not being able to really be together is kind of hard to deal with after a while. At least for me, anyway.