it all depends on the knowledge they have, if as a beginner it is easier for them to play casino, then you should use the casino as the first place to gamble. but for me, I prefer sports, because in addition to hobbies with sports we can also rely on luck as a container for our financial freedom. and it all comes back to us, which one is preferable, because gambling only relies on luck.
You are using both luck on sports betting and casino which invalidate your own statement about advantage of sportsbetting over typical casino games. There is both advantage and disadvantage for this 2 types of gambling depends on the user skills and temperant.
Sports betting is good for user that has a advanced knowledge on sports analysis while it is a total disaster for newbie that don't watch sports that he is betting. On the other hand, Casino luck based game is good for newbie because most of the games are no brainers and have a 50/50 chance to win while advance player will not risk playing on it due to the probability is not in there favor because of house edge.