I'm not going to weigh in on the relative advantages/disadvantages of carrying a secondary weapon as either LE or non-LE.
I will, however, offer an observation that I've seen at least my fair share of folks over the 20 years I've been a firearms instructor experience problems accessing, drawing and firing their holstered primary handguns ... and that was under controlled range conditions where the targets weren't shooting back or punching, kicking, stabbing, cutting, wrestling or anything else during an unexpected, chaotic, rapidly evolving situation.
Now, imagine how much more difficulty a number of those folks experienced when trying to access, draw and fire a smaller weapon they carried as either a secondary or off-duty weapon.
If many of those folks weren't spending the time to practice safely, properly & effectively drawing and using their primary handgun, what are the chances they invested the time & effort in doing so with their secondary weapons?
Having the weapon is one thing. Being trained and experienced in retaining the presence of mind and ability to draw upon the practiced skill in safely and quickly accessing it is something else again.