[JimRed]

they may have been used to contain fire, perhaps to light the cave.

That should be easy enough to determine, as the remnants of ash would remain detectable in the soil.

[gleeaikin]

The article said that they were able to date using burned bone, and there is a photo of fire stained area. It also said the area had been protected by calcite, presumably deposited relatively soon after use by man. I wonder if any digging has been done under this calcite layer, or if they are still just studying the surface.