Although the 2 forms of gambling are online platforms, there are a vast difference between the two. Online casinos are based in wagering on the outcome from a random number generator whereas online sports betting sites you are wagering on the outcome of real life events.
It is also worth pointing out that with sports betting this type of betting often leans towards those who are able to get their heads around statistics. With casinos games are often much easier to play games such as poker people only really need to have a numbers head to play these.
A similarity between the two however is signing up with either online sports betting sites or online and mobile casino you are offered a vast amount of bonuses and offers for both. The only vast difference between these two platforms is the games that you will be playing on both.