Talking about website accessibility, you can have a text-only version of the site or just a color switcher for blind users, for example, to make its contrast more prominent, and therefore, easier to read.
But my question is, what are the pros and cons of each one?
If you have a text-only site then you'll have dual maintenance. Anything you change on your non-text site always has to be updated on the text-only site, otherwise you are not WCAG compliant.
There's good information on "Understanding Conforming Alternate Versions" on the W3 site.
However, it is strongly encouraged to not have an alternate site or a text-only site. Just make your regular site accessible.
As far as colors, you are allowed to have a color switcher but the switcher itself must have sufficient contrast so the user can see it. See "G174: Providing a control with a sufficient contrast ratio that allows users to switch to a presentation that uses sufficient contrast"
