Adding a feature just for the fun of it isn't that unusual in gambling industry. One of the best examples that comes to mind is this situation
on Rocket Men slot, when you have to hit one of those red buttons to launch a rocket that can land in any of those regions(or at least we think so), giving you different prizes depending on where the rocket landed. So, we keep hitting those buttons, getting various prizes, until the rocket lands in the ocean, and the game is over. Every time the rocket is launched, we have an illusion that it can land anywhere, and it makes the game more entertaining, while in reality the whole outcome is predetermined from the very first moment you got that feature: regardless of where the rocket lands this or that time, it is already known how much you are going to win in total.
Sorry for the long read. What I meant was that that lock/unlock feature for The Vault could be there for the entertainment purposes only.
This game attracts me, it is different from all slots, I think when played, isn't that how the North Korean really thinks? Slots for me are one of the games that relax me the most, the truth is that the few times I play it I forget a bit about day-to-day things, the odds of winning would not know how to determine it, I simply surrender to luck and determine how much balance I am willing to lose.
What I find interesting about the new slots is that their intelligent algorithms provide what type of player is who frequents the game, how they play and if the player is bold can determine how they can see profits, if it is short, medium or long term, as outlined here in this article:
Source: https://www.gamblingsites.org/slots/online/