Well, if you talk to a non "knife nut", I would think the idea of rotating knives is odd. But for people that collect & use knives & are into the various "nuances" of a knife, it makes sense.
I've carried a knife since I was a kid. When I 1st starting getting into knives, I had & carried 1 good knife (An Emerson CQC7 which I still have, but don't carry/use anymore). It seemed odd that I would want to change knives on a daily/weekly or whatever basis.
However, as I got into knives, how else are you going to try out different knives then to rotate them? I can't say I have 1 single favorite knife.
Recently, I went out of town & stayed with a friend that's having some health issues. I was there for about a month. It was tough figuring out what knives to take. I didn't want to bring a bunch with me. I ended up taking only 1 slip-joint & 2 different folders.
Currently, I have a small FB for SD (Along with my CC gun), a folder, & a slip-joint for when I need a knife & am around people that might be bothered by my folder.
It's fun & it does serve a purpose in that it's a way to try out & carry all the different knives one may have.
Now, if you only own 1 or so knives, I can fully understand the idea of rotating seems odd. When I really got into knives, I initially thought I'd never own more 3-4 folders, lol. Now, at any one time, I may have 40 or so & that is small compared to many here on the Forums.