The similarities between these two games are that you have no control over the outcome. Every play is statistically and mathematically designed to extract money from players for the benefit of the house. They will let you win 2 games and then you will lose 3. They know that repeated players of this type of game will keep on feeding money back into the system because they get a rush from the wins and they conveniently forget all the losses. Any "technical" aspect to these games is purely an illusion, adding extra features into the game lets the player feel like they have a degree of influence over the outcome and disrupts the play enough that they keep trying to unlock things like mini/side games.
Gambling sites have no control over there. It's just that the house was adjusted in favor of the gambling sites. They have nothing to do with winning at early games. It's just coincidental to others. We all know in the long run that we can never beat a house be it on slots or video poker.
Once win good, get out if can and come back the other day. Unless these gamblers want to test the house for long, then just good luck.
So who then is the house is ít not the site owners that are the House the machine are just the instrument they can set it to whatever way they want, what we should be looking out for is how fair is the house because most of them promise to have a probably fair system meanwhile slot games outcome are in favor of the house leaving the player with lose.