Single driver speakers. Are they worth considering ?

In my opinion nothing less than a three way speaker is worth considering. You’re always better off sharing the work

KEF likes to do single driver point source speakers. It depends what you want. Single drivers have less highs but perfect dispersion. A 3way speaker has clearer sound but horrible dispersion. 

I'm not sure what Kef is a single driver but they do have the small coaxial or point source LS50 which is a 2 driver and nowhere near full range.

Not with a cone speaker, a coaxial is a great idea.. Some think it's the best..

A single coaxial driver, yes. Not my cup of tea.. I've heard some good ones though .. Tannoy Speakers..

Regards

You might be interested in the commentary happening over in this thread for the single driver cube audio speakers: https://forum.audiogon.com/discussions/cube-audio-nenuphar-single-driver-speaker-10-inch-tqwt-enclosure