The article presents a high tech answer to the underlying problem of people being too lazy to update the custom dictionary properly and looking for some shortcut way to avoid doing their jobs properly.

As you point out, misspelling technical words significant to your profession is a quick route to business disaster.

A reader may be slightly annoyed at finding 'the' misspelled as 'teh' somewhere in a document (if the reader notices) but that annoyance is largely because the reader knows (correctly) that the writer did not care enough to bother spell checking the document before sending it out.

On the other hand, the annoyance over a writer who didn't care enough is the BEST that you can hope for when you misspell a technical term. If everything else is spelled correctly but technical terms are misspelled, the reader is likely to assume that the writer is incompetent in the field and didn't know how to spell the terms correctly. An even worse situation arises when the misspelled word turns out to be a correct spelling of the wrong term (this can be quite common is some technical fields where many similar words have different meanings).

This right-spelling-wrong-word will occasionally occur even in non-technical documents due to the way Microsoft Office's spell check system works combinded with the laziness of users who accept the first recommended spelling and click CHANGE or even CHANGE ALL without bothering to look to see what word the spell check is recommending and how it fits in context.