If it's plastikote water based enamel it's fine
A little pot goes a long way. Two coats is best. You paint it on quite thinly and it's dry within a couple of hours although I find it best to leave it overnight before doing the second coat, and then leave it overnight again before putting it in the cage. I once painted the second coat a bit too soon and it stayed sticky for ages.
After that it is dry and hard and quite safe
It doesn't really have a smell and certainly doesn't smell after being applied - and I have a sensitive nose for such things!
I painted a couple of shelves and still had a third of a bottle left, so it does go a long way as it's quite thin and runny.