There are a few advantages of a derrenger. No moving parts. Will slip in a pocket easy and will be on you.
As a back up, as a car gun, as a front jacket pocket it would be great.
The lack of moving external parts you can shoot through a jacket.
I see defensive fire arms in four catagories,
Full size - your standard police fire arm in 9mm, 38 Special, 357 Mag, 357 Sig, 40 S&W, 45 Acp and throw in 10mm, 41Mag and 44 Special
Compact - Chopped and bobbed versions of the full size guns 2 to 3" barrels including the medium fram autos in 380.
Sub compact - Small guns where your whole hand does not fit on the gun.
Novelty guns- Tiny guns that are novelty and are not practical to draw and shoot quickly and reliably. Most hammered derrengers and tiny revolvers fall into this catagory. Two shots may be enough but then again, may not be and the slow reload and this would not be my primary defensive gun.
Now here is where the rub comes, the novelty class can change depending on your size. You have a huge paw and that Sig P230 that works for me is a novelty gun for you as your hand could get in the way of the slide and stop the gun from functioning.
If you want one, get one as long as you can get it in your hand and be able to use it if and when needed.