Any activity you enjoy is enjoyed because it produces a dopamine release (for someone who enjoys it).

People who enjoy reading get the same dopamine reaction from that as people who enjoy video games. Or slot machines.

The difference with slot machines is that the purpose of them is solely to tie that dopamine release to giving away money predicated on deception (specifically, both by not disclosing actual odds, and by lying about them).

A slot game that requires no money to play isn't a problem, because it's not tricking old people into giving away their pensions.