That's different, because they can "control" that (give that money away to people who they KNOW will give it right back.
The $100 royals came off of PURE LUCK, and therefore cannot be guaranteed that the player will play again, so that $400k CAN walk out the door.
Casinos are very short-sighted, often times.
Sure they don't care if you hit a WAP, because they're not the ones who has to pay them (Megabucks, ShuffleMaster, etc)
But hit a super lucky "standard" hit (ie: $100 VP RoyalFlush) and the casino manager/higher-ups will shit their pants and react in panic!
For example, I was pretty frequent at JANugget in Reno; so I was friends with a lot of the employees, including the senior casino manager...he told me that once, a non-player came in, and hit a super-lucky DEALT royal on $1 10-play (highest amount royal you could win in this casino; $40k) and the Ascuagas FLIPPED OUT and wanted any video poker that would allow for higher than a $8000 royal removed! He tried to calm them down as much as he could.. But they still ended up removing a LOT of $5 denom single-line, and all their $1/$2 multiplay...
The Ascuagas sold it finally, and they now have the FireBet, but it's the crappy payoff one (starts paying at 3 points, and I think only pays 200:1 on all 6)