I've spent most of my life looking forward to accumulating the next gun...and generally I had to wait on $. A good thing is my whims and my fotunes are not in synch.
Is the cartridge important? Generally,I first choose what I'm going to use the tool for. Whats the job? That could be leisurely plinking,drilling holes in paper,or desperately fighting to stay alive. Or the instrument I choose as part of a plan for a hunt.
And yes,in each case I choose a cartridge,or some acceptable cartridges. I choose based on (IMO) sensible parameters,temperedd with my own quirks.
I really can't argue the .257AI or the 38 Super are "best" at anything...but they will do just fine.
I handload. Each new cartridge means new dies,different bullets,maybe a new powder or two,new brass,used brass,and at some point a guy notices he's just got too much crap. Way too much.
Don't get me wrong! You may enjoy your .25 ACP and your 32 all you want!
If I'm going to carry for a desperate life and death moment,its not going to be a 25 or a 32. I'd compromise for a pocket 380 or 9x18,under the idea"The gun in your pocket holster beats the one at home in the safe"
But IMO,for myself,a .380 is minimum,and the compact 9 mm's...Really,I can compare a Shield 2.0 for weight and compact size to a PA-63,a Makarove,the Berretta 81,the 007 Walther,etc.
Now lets look at getting the job done. The WW2 battle pistols. Mostly 9mm or 45. Mag capacity from 7+1 to 8 or 9 +1. The Shield matches the cartrides and mag capacities. A 45 ACP Shield is 7+1. So is the WW2 1911.
Lugers? P-38's? The Lahti? 9mm and maybe 8+1 ? All the guns over 2 pounds?
Shield? a 20 OZ + or - gun. No DA/SA safety fumbling. Striker gun,draw and fire.
Price?? The S+W is + or - $400.
Why would I carry something a lot less,or a lot more,in most cases? Mag capacity? OK,my M+P 9 C is a lot like a double stack 12 round Shield.
I don't need or even want 25's.32's,etc taking up time,space,and resources. I could stretch to having some little pocket 380 like a Ruger LCR,maybe. But I'm not even thinking about wanting one. You have fun.
Its easy to poke fun at a Woman's closet full of shoes. We can do the same with guns.
Sometimes,we reach the point of realizing "Less is more" But,till you get there,"He who dies with the most toys wins?"
Now,a black powder cap and ball...could be a lot of fun....