The extended edition is, "Never, ever trust a fucking safety."
In terms of raw engineering, you only need a grand total of four parts to make a gun that can fire. Four, that's it. Everything else is a bonus feature.
That said, a few hundred years of tech later, and we've gotten about as far from the base four as an SUV is from a horse cart. A Glock has about 30 parts. (A 1911 or Sig P226 has about 50 and a Beretta 92 has about 70, just for bar trivia purposes). Damn near all of these parts are designed to make it easier to fire.
The safety, on the other hand, is designed to make it harder to do so under certain circumstances.
So not only is this tiny piece of metal designed to work in opposition to proper function (and therefore as prone to malfunction as any other mechanical device), it's outnumbered by an order of magnitude by parts that are designed to work in conjunction.
Just to translate the five-dollar words so we're all on the same fucking page, with everything else designed to make shooting easier, it's all alone in trying to make not shooting easier.
So yeah, use it if you choose it.
Use it if your facility or agency is making you use it.
But for the love of winks and smiles, never fucking trust them.