This is just my experience please get your own advice and do you own research to find out if this is good for you.
I have been using the hyG Ionic Toothbrush since 2011 it uses negative ions to loosen the bond between teeth and plague effectively making a toothbrush that can be used without toothpaste. The first time I used it I felt my teeth were cleaner than they have ever been. I tried not using toothpaste for 6 months, after my teeth still looked and felt completely clean except there did seem to be a little yellow tinge. I brush once with normal toothpaste and the yellow tinge went away. My dentist is amazed at the condition of my teeth. Although I have a very healthy diet too.
So I use it now and then with toothpaste. I have a toothpaste with the B12 vitamin in it when I feel I need that I use toothpaste or when I am travelling on plane and get free toothpaste use that.
The advertising brochures talk about the convenience if you are travelling or camping and don't have access to toothpaste.
In the photo is my second toothbrush in 5 years and I have replaced the head numerous times of course.