We always see a lot of bickering and contradiction in threads on this topic.

One perspective is that since people are not perfect and can make mistakes, a manual safety is desirable. They will say the odds of actually needing your gun for self-defense are very low, but you carry and handle your weapon very frequently, so a safety just makes good sense. If we are going to go by the odds, then carrying a gun could be considered unnecessary.

Another perspective is that a manual safety is simply not needed and adherence to safety guidelines and proper training mitigates any need for it. Individuals with this viewpoint will assert to keep things as simple as they can be and that it's possible to fail to get it disengaged, especially during the stress and urgent pace of a life and death struggle and therefore shun manual safeties.

If failing to get it disengaged is possible no matter the training, then making a mistake and having an unintentional discharge is also possible no matter how careful someone happens to be. There are merits to both perspectives, so it's a matter of finding the right balance since there is no factually correct or incorrect answer for every individual.

I'm not perfect and realize I can and do make mistakes and the right balance for me is no manual safety and a heavier trigger pull. This keeps things as simple as possible while adding an adequate measure of safety. I do not feel my DAO revolvers need a manual safety nor do I feel my NY trigger equipped Glocks need them. If I bought a Shield, I would get the one with no manual safety and the MA trigger. A lot of folks will say marksmanship will suffer with a heavier trigger pull, but not all that much from my experience and surely not enough to matter in the close and fast scenarios of civilian self-defense. People always talk about proper training, but how many actually engage in realistic self-defense training in context? Very few in my opinion.