I mean, for example, to set a range for creating an address in a specific range, I want to create an address in 2 ^ 135 - 2 ^ 136 with a specific mask
For VanitySearch, I don't really see the interest of this options and it is a good way to see its funds stolen.
May be it can be useful for bitcrak, if you have detected a failure in a wallet pseudo random generator and you know more or less subspaces of generated key.
in order to get access to the internal state of the algorithm the attacker just needs to get a sequence consisting of 624 numbers