I’m running a full disc wheel (Alto) tubeless. Had a issue last week getting a tire to seat properly. Took it all the way off and the tape had moved/overlapped and bunched up.
I took the rim tape off and noticed the rim bed is smooth carbon. No nipples, holes, or sharp spots anywhere.
Left me wondering if it’s even necessary to reapply rim tape or not.
Rim tape is only needed to cover the spoke holes. It is not needed if the bead is undrilled (except of course for the valve stem hole).
I have a pair of Mavic Ksyrium Elite wheels that I ran tubeless w/o rim tape, since they have a non-drilled bead.
I have a holeless rim bed on both my tubeless wheelsets. No rim tape necessary.
Besides making it tougher to build by putting the nipples in through the valve hole, I don’t see why all tubeless wheels shouldn’t be built this way.
Shouldn’t be needed.
The tape is to seal the rim because of the holes for spoke nipples.
No holes, no need for tape to seal the non existant holes !!
I’ve seen some other rims that don’t have a drilling on the tyre side - e.g. Mavic Kysirium wheels (the nipple threads into a tapped hole in the outer rim wall).
They even state no rim tape needed
“…Fore drilling technology doesn’t require the use of rim tape” from the Mavic Web site
Besides making it tougher to build by putting the nipples in through the valve hole, I don’t see why all tubeless wheels shouldn’t be built this way.
Yes, but that translate into $… it’s a competitive world out there 
Besides requiring 5min putting tape over the holes, I don’t see why all tubeless wheels shouldn’t be built with easily accessible nipple holes
FIFY
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And, when a spoke breaks close to the nipple and the threads are corroded (thanks to saving 5 grams by using Alu over brass nipples), it is a total and utterly fecken PITA to sort - because you can be sure the broken spoke/ nipple is the opposite side of the rim to the valve hole, and the gap to get it to pass through that inner chamber is smaller when all the other spokes are in place.
Besides requiring 5min putting tape over the holes, I don’t see why all tubeless wheels shouldn’t be built with easily accessible nipple holes
FIFY
Tape degrades and eventually fails. Holeless rims just work. How often do you change nipples?
I’ve had almost zero issues with spokes/nipples in 20 years of cycling, but several slow leaks or cut tubes because of rim tape.
Since I build several of my own wheels (or change shitty spokes in manufacturer wheels), I’ve likely spent quite a bit more time with nipples than with rim tape
Also, even if we assume manufacturer supplied wheels, I’d go with drag saving internal nipples over no rim holes any day Using proper rim tape I’ve never really had any problems worth talking about. Using shitty rim tape, sure - that’s why if a manufacturer supplies shitty rim tape I ditch that and install proper tape as one of the very first things.
ETA: Just thinking back, the only wheel set I’ve built that I’ve worn down so far (brake tracks close to gone and a nipple pulling through the rear rim) I had to change a spoke in the front rim after a small mishap once, but didn’t ever have to remove the rim tape (other than to change that spoke).
Back to the OP, I had a similar question with my tubeless disc wheel so asked the manufacturer. They confirmed that whilst the tubeless tape isn’t strictly necessary (i.e. the rim is already “airtight”), it can help when getting the tyre to seat as the tape is a smoother surface than the carbon inner rim channel. It’s easier for the bead to slide over that smooth tape surface and over the bead locking ridges apparently.
Makes sense to me so I always run with a single layer of tape.