Manually downshifting a Toyota automatic transmission harmful?

My CX-5 will *automatically* downshift when going down hills, and exceeding the cruise control set speed.
I'm sure Mazda knows a hell of a lot more than internet forum posters.
My Tacoma also automatically downshifts from OD to 3rd gear if I am going downhill for a while (no throttle) and then apply the brakes. Pretty cool for a 2006 model. No cruise control involved when it's happened in this truck. My very intelligent Toyota fanboy friend didn't believe me, so we went for a ride and he was completely shocked.
My 4T65E will downshift on its own when I apply the brakes and coast to a stop; however, it's barely perceptible.
Anytime you are inputting energy through a system you are creating wear. I'm much rather replace brakes 2x as often than risk wearing out a tranny.
Thanks for the replies thus far...

Would I be correct in assuming that those of you who are saying to keep it in "D" and use the brakes are implying that I am somehow damaging the transmission by forcing downshifts to slow the car?

In the alternative, if there is no harm to the transmission, I am increasing the life of the brakes by so downshifting, which is a net gain for me...

The crux of the question is: Am I doing any harm to the engine or transmission?
People actually do this? :unsure:

Nobody shifts their automatics manually even with tiptronics that are designed for shifting manually :D
I do all the time in my daughters '12 Scion xB (used to be my wifes and I drove it a lot) in my wife's '18 Hyundai Santa Fe and in my "spare" '04 Hyundai Sonata with a tiptronic setup.

To the OP, shift if you want, won't hurt, really won't help either. More work than it is worth IMO.
My Son's Scion tC has the same shift pattern as the Camry, and is a pain to mess with. The tiptronic in the xB (same transmission as the tC, just different shifter mechanism) makes it easy, but having to make the shift lever dance around (especially downshifting) is not worth it on a regular basis.
gosh I hope not. I have a toyota HL with the 2GR and 8AT and slap up to 5 gears out of the way every hill, especially when pulling the boat. these trannies are all clutch to clutch nowadays and 100% PCM controlled so if the PCM lets the solenoids fire - it must be ok. Toyota does not screw up in this area.
For sure, that is why the law exists but I'm not sure if there are exemptions for passenger vehicles. Not that I think the police will bring in a Camry driver for downshifting. That would be funny.
Me: Clicks O/D off button in my Camry
Or when driving in hilly, mountainous country one might downshift to avoid lugging the engine. If you let the engine choose the shift points, all too often the trans will shift in and out of gears, which causes more wear than, for example, downshifting into 3rd or 4th and leaving it there. I've driven my Camry through the mountains for thousands of miles, and using the shifter in that way is a smart and good option.

Toyota included the sport mode in their setup for people to use in an appropriate manner. Remember, there's really little, if any, difference to the trans if the driver chooses the shift point or the trans makes the choice.
The old ECT switch, I haven’t seen that in a while(it’s kinda back with the drive mode knob on Lexus and the PWR button on the Prius). All I know is that ECT PWR sets the shift points higher, ECT ECON shifts early. Lexus RWD models had ECT SNOW to start in 2nd gear, to reduce wheel spin. I use the Sport mode or shift out of D to 4/3/2 as appropriate for engine braking or to keep the trans from hunting gears on uphills.