The Voynich Manuscript is a cipher because...?

[Emma May Smith]

I'm curious to know what the best arguments are for the Voynich manuscript being a cipher.

I'm specifically interested in the thoughts of those who believe in a cryptological solution. What made you follow this path? What do you consider strong evidence for it?

I'm most wanting the positive arguments rather than the negative ones: why it is a cipher rather than why it isn't one of the alternative solutions.