Not sure why others are doing it, but the switch is kind of a boring console imo. You may as well just use one of the million PC handhelds with the same form factor, and persistent hacks require a hardware mod.
The 3DS is a fun pocketable form factor which a lot of people already own and easy to permanently mod on any firmware version or hardware revision.
I'm surprised no one has mentioned online: most people don't want to risk console bans, and that immediately makes jailbreaking their Switch a non-starter
At this point most people getting a 3DS are probably doing so specifically to jailbreak it
Most people use an EmuMMC to avoid bans. I think the bigger issue is that most Switch consoles need a hardmod.