Actually, what is tenkeyless? 87key layout? Or anything without a numpad? Is ErgoDox or TypeMatrix 2030 tenkeyless then? Because TM2030 has an embedded numpad with the same grid layout as the "standard" keyboard.
TKL is usually an 80% board (87 keys, technically about 83%) i.e. a conventional alpha-numeric section, separate function keys, separate arrow and 6key clusters.
Ergo Dox is a separate category of ergonomic keyboard.
TM2030 is something else again.
It was a rhetorical question. ~_^
The problem with this thread is that it assumes the 104key layout (aka fullsize) is "normal" and then there's the 87key layout (aka tenkeyless) that is exactly the same, but doesn't have a dedicated numpad on the right. However, many of us use other layouts—either with even fewer keys, or similar to 96key layout, or completely different (ErgoDox master race!).
If tenkeyless means 87key layout, then my answer to OP would be that IMHO there's no point in using that, because there are more compact keyboards with the same amount of useful keys (at least in theory).
If tenkeyless means without numpad, then I have to ask, whether compact ergonomic/point-of-sale keyboards with embedded numpad are tenkeyless, or not.
Either way, grid/columnar layout FTW!
...and naming conventions are a mess.
Maybe the question was just meant as "do you use numpad?"...