I think a fellow (or gal) ought to use whichever platform lets them sleep at night and the one they have the most confidence in. I still carry my revolvers. I've had several decades of training with them. I like some of the advantages of the semi autos, especially the ones that draw and fire with the same exact steps I took for all those revolver years. I'm too old and do not have the time nor the desire to retrain myself to another system where I have to remember which platform is in my holster. Yes, training is very important, but so is the "keep it simple, stupid" axiom, especially when operating under severe stress during which time your brain is very likely to revert to whatever method has been solidly programmed within it. For me, that's a weapon that does not require swiping off a manual safety, which in my mind is redundant on these weapons. I have also trained most of my life to keep my booger hook off the trigger until I intend to fire. That's what makes 'em go off, you know?
Nothing is fool proof and anything can happen. But what is most likely to happen is what is firmly programmed in the computer. I am loathe to try to start a new operating system for the times my life depends on it most.
As I said before, the manual safety on most striker fired weapons can be used or not without fear of that weapon just going "OFF" on it's on. My manual safeties have not and ever moved from "on" or "off" unless I have purposely moved it. So I don't mind if my Shields or my M&P's have it installed or not. I will happily buy either way, and happily use either platform. I just choose to leave the manual safety off all the time, unless for some heretofore unknown reason I should decide to use it, after which I pray I will remember to move it to the "off" position again. I DO NOT say anyone else should do as I do. I just do not see why this topic generates such discussion. If you want a manual safety, please get one and use it in good health and happiness. If you think for some obscure reason that having a manual safety in place will make your weapon less safe or less efficient, then please don't get one!
There is surely room for all of us on either side of the question Ain't it grand that we have the choice? I'll happily let you chose your extra safety if you'll give me the room to chose none or not to use the ones I have! Thanks for listening.