A lot depends on your usage. If you commute a few miles through town to go to work, then it would probably work on a bald tire maybe up to 40 mph, after that, good luck. A tubeless tire doesn't like bald or sidewall cracking. A tube type tire may let you run a worn out tire longer.
How much is your life worth? Replacing a tire a little early is a good idea in every way.
I learned this the hard way. I started a trip to Sturgis on my Electra Glide, with a rear tire that I thought looked okay for the planned trip from Southern, Calif to Carthage, Missouri, through Iowa and west to Rapid City and then after the rally, went west through Montana, Wyoming, and into Boise, Idaho when the rear tire that I thought would be fine for the entire trip was found to be bald and showing a few cords!!!! I had it replaced at a Harley Dealer there and proceeded through Oregon to the coast and down to CA again.
The point is that tire worried me from the time I left home. If I'd had enough sense to start with a new one I wouldn't have had to wait a day to have it replaced on the road.
If you have or cause a wreck because of a bald tire failure, it could become an insurance issue and law enforcement issue.
Sam:coffeescreen: