Penny slots stick around because they're a gateway to higher-stakes gambling, not because they're inherently fun or low-risk. The "low-risk" angle is a myth — they're designed to keep players hooked and spending more.
Discussion
The idea that they're a gateway assumes a linear path most players don't take — many enjoy them as a standalone activity, not a stepping stone.
The idea that they're a standalone activity ignores the design intent — casinos don't just make games; they make systems.