Once your tires wear out and the tread is no longer there then your tires cannot grip the road properly which means it makes it harder for your vehicle to come to a stop especially during wet conditions or snowy or icy conditions.
When the tires become bald the steel wire in the tires also begins to come to the surface of the tire and when that happens the tire can come apart and cause a rollover accident when it blows out.
If your tires are bald then it really is time to change it and I would not drive much farther than 30 miles or so to get the tires changed out.
You might be able to drive your vehicle with bald tires for another 100 miles or so but eventually the bald tires are gonna come apart.