'Zero Frets are used on Cheap Guitars!'
{ quoting from an article in Wikipedia titled ZERO FRET }

what an ignorant statement by Wiki,
- the evidence points the opposite way -
as we will see in this and the next page...

First, let's look at 'cheap' guitars that have a zero fret.

the 'cheap' Kent 820 guitars have a zero fret.
click on the image for larger detail.

Check this out!  Now there is a Zero Fret Kit
to retrofit ANY fretted string instrument!

'Cheap' guitars?
Wikipedia does not know what they are talking about, folks!
the fact is that G
retsch, Hofner, Magnatone, Mosrite,
are anything BUT  'c
heap'  guitars; 
those are highly desirable guitars for which guitarists
and guitar collectors pay lots of money.

Reasons for a zero-fret?
Lower action, comfortable playing, and more string resonance.

My Experience
I feel qualified to talk about the zero fret because I've played with many guitars that have zero frets, and many that don't, for almost 50 years.
I can say that the zero fret is not only a very elegant way of making a guitar, but it also makes for a better playing guitar. When the Japanese started making guitars with a zero fret, guess who they copied it from?

But wait!  There's MORE!  let's look at famous players who made their mark with 'cheap' Zero Fret Guitars...
The Zero fret
click here to follow this story
© JAMR 2019
Brian May's guitar has a zero fret !
The Guild and RS Brian May Model guitars come with a zero fret !