this is, imho, a question of personal experience and preference.
I have a Glock 19 - no external safety of any kind. at home, in the bedside stand, not a problem, to me. but I do not CC the Glock - it's like not non-printing, for openers....
my daily CC is a Walther PPK/s - external safety + double action for first shot. i.e.... when I'm wandering around areas where self-defense is highly probably . . . the safety is off, and the first round double action provides a degree of 'not likely to accidentally discharge on draw'
I have, and routinely CC, the M&P Shield 2.0 in 9mm. with external safety - and I'm not at all happy with the design change from a flip down lever to a embedded button . . . regardless, same approach used - in an iffy area the safety is off. whether IWB/OWB/Sticky on the console, , ,
not enthralled with having to flip off a 'button' safety.
given a military background of the 1911, I'm muscle programmed to flip the thumb safety when drawing the weapon. curiously, the M&P compact .22 has that (near) identical design - the PPK/s, the Glock, the Shield 2.0 does not.
anyone aware if the Shield 2.0 / 9mm can be retrofitted with a thumb flip external safety?