"The casino earned $10,236 per game last month from 6,749 slot machines while earning $12,484 per game last June from 6,078 slot machines. But the payout percentage to customers rose from 91.51 percent last July to 91.64 percent in July 2009."
Offset the much higher VP payout %, and you can figure out how valuable the slot grinders are to Mohegan. Hopefully the slot promotions will still spill over to VP players.
Quote is from the Norwich Bulletin:
http://www.norwichbulletin.com/casinos/x1528798792/Mohegan-Sun-revenue-from-slots-rose-in-July