There are a lot of reasons why I prefer sports betting over poker. One thing I like, is that I can readjust my bet size every day. You can't do that in Poker. In poker, you are stuck at the same stake level, until you have enough buy-ins for the next stake level. So, if you can get a decent number of sports picks each day, using a decent bankroll management percentage (3% or higher is great,) you can grow a bankroll quite fast. Another thing, is that the upside of sports betting is much better than the upside of poker these days. With all the changes at Pokerstars, it's not so lucrative any more. The big money is still available with sports betting, but not so much with poker.
Yet another thing for me, is that I really hate the idea of mass multi-tabling. I don't like it. You can only really grow a bankroll fast with poker if you multi-table. Otherwise, it's a slow crawl compared to sports betting, IMO. There is also the ability to do sports trading, instead of sports betting. I have never done sports trading personally, because none of the exchanges accept Canadians. But it is a popular option for many people around the globe, and it is an alternative method to make money with sports. In addition, fantasy sports provides yet another method for making money at sports, though I don't think it's super-lucrative.
Last, but certainly not least, is that your skill level does not need to improve as you move up the stakes in sports betting. You can win with the same R.O.I. betting $1,000, as you do betting $10! This is what I like the most about sports betting. In poker, your win rate drops as you move up the stakes, and consequently you always need to be improving. Those are some of the reasons why I prefer sports betting to poker.