Hello: Clarity is good 😎 Showerheads drip even when the integral valve is off, so that you know the water supply is still on. If you had a positive shut-off, it would be tempting to leave that closed while keeping hot and cold on and at the right temperature mix. This creates a cross connection between hot and cold, upsetting the entire water distribution system. Check valves can be installed, but simpler is better.
Any showerhead that gives you bigger water droplets at slower speed will carry the heat to you better and mix in less cool air in doing so. The result is a warmer shower and less of that unhappy result of warm head/ cold feet, that happens with some bargan showerheads.
You’re clearly on the right track.