Of course it beneficial to jettison that load prior to riding.
1. Improves flexibility
2. Improves comfort.
2. Reduces the likelihood of having to stop to jettison the load during a ride. Damn bib shorts.
3. Minimizes the weight you have to haul up the hills or accelerate in a sprint
4. It's just plain healthy to get rid of sh*t.
Just do it. You'll be happy you did.
It's best to use a bidet too. Nice to be clean.