Your theory makes sense, and is more plausible than a VERY low limit table or two at the hotel itself. The Pioneer Club did use other dime chips for low-minimum games, like other downtown places that offered 10c minimum craps games. (I even played at a dime-minimum craps game offered downtown as a starter game before noon. Those are long extinct now though! )

In considering how/why Pioneer Hotel might have offered (only) a table or two, I recall how the Travelodge-Las Vegas motel (on Tropicana Blvd.) was basically just a motel. But in the front corner of the lobby, they had a handful of slots and just one, or perhaps two?, BJ tables that operated on occasion. But their live gaming used chips from 25c up to $25. I was only in there a couple of times, but it was a size anomaly. NGCB must have approved it though. IMO, the very limited gaming was so they could say they had "live BJ and slots" for competitive reasons. Just my speculation.