I’m firmly tubeless on my MTB. Tried Tannus inserts on my commuter for about 6 months – only reason I didn’t go tubeless at the time was tyre/rim combo.
PITA to fit – I dropped down a tube size to account for the spce within the tyre volume taken up by the inserts, but still a faff as the insert wouldn’t stay centred in the tyre (more faff than tubeless IME). Had one puncture in 6 months use due to super-long thorn which penetrated the depth of the insert and punctured the tube. Fitting a reaplcement tube on dark, cold, wet trail – cos it’d never happen in the dry – nearly exhausted my swearing vocabulary.
I since succeeded in tubeless using the same tyres and rims and binned the Tannus inserts.
Not worth the faff for me. YMMV.