Not at all if you don’t mind Methane and other carcinogenic fumes from entering the bathroom.
Some folks actually enjoy the smell of nitrous sulfide in the home.
If your older and not concerned about cancer then by all means save the money a trap would have cost you.
Traps are only for cowards and morons who follow health codes REAL MACHO folks dont use traps or sun screen or care what is said about smoking.
Go for it, no pain no gain