I beg to differ. Most of the arcade games of yore were gated on skill; you could avoid having to pop in another quarter if you played well enough, and that was where the fun came from.
Where is the skill and gameplay involved in spinning a virtual roulette wheel until a powerful enough unit or item pops out to let you advance to the next level of gameplay? And, of course, the answer is that there is none; it's merely taking advantage of those prone to gambling addiction.