Running tubes in a tubeless tire and wheel leads to rust damaging the wheel.
A tire that won't hold air, will also let moisture in and when there's a tube in the wheel, that moisture becomes trapped between the tube and wheel. The majority of OEM steel wheels that I've seen with tubes, are ruined and won't seat a tubeless tire again without heaps of bead sealer, if at all.
Besides, with a flat, you'll have to break down the tire to repair the tube instead of easily sticking a plug in it. ATV tires are more difficult to break down by hand than 18 wheeler tires, and I've done a lot of both.
Tubes aren't that inexpensive either. I'd just replace the tire.
The story of three wheels and a man...