Niches for my handguns include such things as:
(1) a mouse sized semi-auto that I can shoot reasonably well at moderate distances (25 yards and in). I have a Sig P238 for that.
(2) for when I'm wearing cotton shorts with a drawstring and elastic waistband, I need a mouse gun that is light, even if my effective range is 10 yards or less. I have a Ruger LCP for that.
(3) a more powerful handgun that I can fit in most, but not all, of my pants pockets. My Kahr CM9 covers this.
(4) a "lightweight" 1911 that is very concealable in .45 acp. I have a DW CCO for that.
(5) for practice and backup to the CCO, above, a steel framed 1911 of the same size. That's my Baer Stinger.
(6) a full sized 1911, steel frame, in .45 acp for OWB carry and/or home defense. I have at least one for that role.
(7) a full sized 1911, steel frame, in 9mm cause it's cheaper to shoot 9mm than .45 acp.
(8) a full sized 1911, steel frame, in 10mm just in case a black bear wanders into my city of about 300,000 (don't have to worry about grizzlies)
Well, you get the point. If I want a gun, I can find a niche for it. Having said that, I have contemplated getting rid of a couple of handguns I don't shoot and/or duplicate other guns.