The risk is if you need to move car immediately you have a delay. If your leg hurts holding brake guessing your reaction time might be lower.Never.
You'll be causing a small amount of wear having those 1st gear clutches apply and release all the time. Not a lot, but more than you would just leaving it there.
Although if your vehicle has auto stop-start it might be handled differently.
With my manual transmission cars I usually knocked it into neutral while coming up to the stop if I knew I was going to be coming to a complete stop. Usually without the clutch being involved.
I keep hearing people talk about added wear but it's no different than putting it in gear every single time you want to move the vehicle. It won't hurt the transmission, it's designed to go in and out of gear. Your engine and transmission heats up pretty fast at long stops when left in gear.I held my foot on the brake the whole day today. It wasn't too bad. I envy you manual transmission guys.
My Accord has a brake hold feature that will let you rest your leg at a light. Basically, it applies the brakes for you when you hit 0 mph and holds them until you tap the gas again. I don't care for it.
+1Yes I put it in neutral if it has just turned red.