I recently made the suggested edit to:
The edit transcribed the text of the image to the page to gain the following benefits:
Visibility and ranking on Google
Granted, people can search by image on Google, and this page should come up if you search for the image.
The thing is, Google doesn't default to searching by image, it defaults to searching by text; people searching for searches around/related to this topic (e.g. "can pi be used to represent all words in the English language?") would benefit by having the text transcribed on the page.
Why is this important? Because from day one, Joel and Jeff designed Stack Overflow, and by extension, Stack Exchange, for pages to turn up to people that type into search engines.
Jeff has written extensively on the the importance of Google and search engine visibility.
This is not Stack Overflow, but all of Stack Exchange shares a set of basic tenets; this is absolutely one of them: to gain new traffic (always a good thing) which has the potential to get new users who will contribute to the site (another good thing as well).
For those that use screen readers, accessibility issues, that image renders the question worthless to those people. From Wikipedia's entry on web accessiblity (emphasis mine):
For example, when a site is coded with semantically meaningful HTML, with textual equivalents provided for images and with links named meaningfully, this helps blind users using text-to-speech software and/or text-to-Braille hardware.
By not providing the transcript, you're reducing the overall accessibility of that page.
In summary, the edit would have provided reach for new views on the site (which could possibly translate into more members) as well as make the page more accessible to everyone who could possibly view it.
In light of those two benefits, why was the suggested edit deemed "pointless" and "unnecessary", especially when I took the time to point out one of the big benefits in the description of the edit?