As far as a safety goes, I can take it or leave it. I used to insist on a manual safety, but after carrying for a while I've become more accustomed to, and comfortable with, a gun lacking a safety. The last five handguns I've purchased have not had a manual safety. One of them (XD45 Tactical) I no longer have, I use one (Ruger P90) as a bedside gun, and three (HK P2000SK, Taurus 605, Sig P232) for carry.
I don't think safeties are a necessity, but if it's more comfortable for someone to carry/shoot that way, then who am I to say otherwise? Different strokes for sifferent folks, as the saying goes. I also find that most safeties (with the exception of 1911 and HK USP) are difficult for me to operate with my shooting hand because of my hand size. It's hard enough for me to get a good grip on a doublestack .40 SW or .45 ACP.
Personally, I've become so used to carrying a gun without a safety that I'll probably never go back until I get a good 1911 for carry. But then it's going to be a matter of retraining myself.
Do whatever works for you, and train to deploy your gun in such a manner and you should be all right.