Whenever I roll for a new cat it just shoots me blanks
Ok, yes, this bug hasn't been fixed in years. To make sure you aren't wasting coins, make sure to check the list first. It disappears after you acquire some cats (somewhere in City & after), so you may have to sell some cats/set cats free before it reappears. For instance, if you want to get Princess Leaf by random luck/goldcoin, but also keep uwu cat (the adorable one), you need to try to get the former before playing the latter.
Hope this helps!