The more reason slots will more likely to cause addiction, because, you can access it anytime, anywhere, without the restriction of scheduled gameplay unlike sports betting.
Yes, well, that's true compared to sports betting but nowadays you can play roulette or say 24/7. The physical slots have some sounds that are made to hook people, and in online they are similar but the other online casino games also emit that kind of sounds. They are sounds that enhance the excitement of gambling and it is the emotions that hook people. So it is clear that slots are more addictive than some types of betting such as sports betting but compared to other casino games I am not so sure.
I remember years ago seeing a person who had just cashed out spend all his paycheck on slots, who knows how many people this will happen to today playing online.