General failure mode for failed bearings is that they start getting noisy and the volume of rattling increases.
Then either the bearing race destroys itself, or the thing seizes.
Either way, it will not be pretty.
The washing machine drum runs naturally unbalanced (due to the uneven spread of wet washing), so the bearings are designed to keep the drum rotating reasonably smoothly.
I'd expect the thing will only last for a few tens of washes, if that.
You'll notice some hot smells coming from the machine as the belts over-heat due to the extra torque needed to drive the drum.
or one day, the thing will stop with a massive jerk.
Probably not desperately unsafe, though there might be a fire risk, if the belt overheats too much.
Whatever, you won't get much extra life out of it. I'd start preparing for a replacement pretty quick.