for several reasons,,,,,,,
for build quality, for the year warranty, for the ease of fixing if there is a problem, for the lack of problems those who have them have,,,,
a ton of reasons

I'm tired of replacing devices,,,,,,,,,,I haven't even RECEIVED my Vamo yet, and I've done nothing but read about cross threading problems,,,,,,,My twists last 3 months, my Volts last 3 months,,,,,,,then they die and I have to replace them. I'm sick of it,,,,,,,,,I want a quality mod, easy to fix, that can take a licking and keep on ticking, that can be depended on to work a year from now.
having made my choice, however, I can certainly understand why some people wouldn't make the same choice,,,,,,,
nothing wrong with that, IMHO. Everyone's different