I kind of get the people who don't want to try road tubeless. There is a bit of a learning curve.
For a mountain bike. Well, aha, all the cool kids ride tubeless. It is the pool noodle in the tire that I don't get.
Tubes on a Fat Bike? Are you going to ride on soft sand or snow? You really need to find a new LBS. The ability to run at very low pressures on a Fatbike is the reason to run tubeless. Better float on soft surfaces and better grip on climbs and corners. The flat resistance is another good feature. The weight saving is the bonus.
There are really no "gyrations" and no "rigmarole". Get a syringe to add sealant, and don't use a sealant intended for wheel barrow tires. I run studded tires in the winter and plain tread for the summer. Orange Seal subzero has lasted a whole season for me, so I put fresh in when I swap on / off the winter and summer tires. If I wasn't swapping tires I would just top up the sealant twice a year. It is less effort than maintaining air pressure in your tires or keeping a chain lubricated.