Auto Transmission's Solenoid

Hi. Does shifting into neutral on my auto transmission car when I’m coasting downhill or stopping for a red light cause problems for the trans’ solenoid (or any other problem)?

My bro, a part-time auto-mechanic (and electrical engineer), thinks it is not a good idea for me to do that.

It’s a bad idea.
It adds wear and tear to the whole drive train.
It uses more gas, instead of saving gas.

Please name a good reason for doing this?

No, it won’t cause problems, but it’s not necessary, and possibly dangerous. You may accidentally shift into reverse while “coasting downhill,” and that wouldn’t be good.

I like the coasting feel of the car better - it feels more like the manual transmissions I learned to drive on (and which real men drive :0).
It’s easier on my back if I don’t have to hold the brake while stopped at a red light. I can shift my weight around.
I get to hear everyone honk at me if I don’t anticipate the green light because after I shift it in gear I have to wait for the ‘gears’ to ‘catch’ before I press the gas.

You may accidentally shift into reverse
That seems unlikely. I just push the lever out of D. It is prevented from going into R if I’m not pushing the lever’s button.

Ask all the people who thought it was “unlikely” and then did it by mistake anyway!

If you don’t like an auto trans, why not buy a car with a manual? Or an autostick automatic?

It’d be pretty hard to quantify whether you’re doing damage or not, but it’s kind of silly.