The main use is to assert control when the driver may be unreliable (like during
power-up). We don't know what your 3.3V is doing, nor how you're using the FETs
nor the consequences of misbehavior. These are things you have to think through
based on your particulars. What happens if (say) your gate was allowed to float
to 1.5V and put the FET into a few ohms on resistance state, maybe oscillate?
If you don't know, then you may want to just safety-strap it. But that costs
precious battery power all the time when "on".
Free answers are nice but they aren't a substitute for analysis and judgment.