I’m one of those weirdos who actually really likes using a smaller keyboard so I’ll give you a few reasons I like smaller keyboard and a few why I don’t like larger ones.
First of all, desk space. I have a very small desk so not having the numpad makes for a lot more space for my mouse.
I also find when gaming that my arms fall at a weird and uncomfortable angle when I have the keyboard and mouse at a comfortable distance apart.
I don’t tend to use the numpad, or 9 key cluster above the arrow keys very often so the ones I do use (delete, Pg up and Pg down) are just mapped to a new layer. My board is ortholinear so I’ve also got the numpad mapped to a layer if I ever want to use it.
The function row is also re-mapped over the number row with the - and + acting as 11 and 12 because I very rarely need to use a function key and a number key at the same time or in quick succession so theres no need for the seperate keys.
I don’t program much but when I do, I’ve got all the relevant symbols labelled with their layers on the front of the cap so they’re not hard to find when I need them.
I’m also very much not a tidy desk person and I do a lot of my hobby work at my desk so having a nice small keyboard I can cram wherever I can when I need it and just move out of the way when I don’t means I’m not always shuffling stuff around my desk to make space for this huge keyboard.
Overall however, I just really like the look of a nice, small, compact keyboard with everything I need just there. It’s visually nice to have a uniform block of keys with no gaps, no larger or differently shaped keys, and that’s just not something a larger keyboard offers me.
I can absolutely see how this sort of thing doesn’t work for most people because there is an element of having to re-learn muscle memory and such, but for most people that have tried it, they seem to find that when it works, it works very well!