True but that was given as an example not a single data point. If you wish you can do a little research and see that spelling is considered a poor indicator of intelligence by virtually everyone that is in the business of measuring intelligence.
The more effort your audience has to expend on mentally translating what you've written into English, the poorer a communicator you are.
Typically in business communication via a written medium people can take advantage of spell check.
Typically in business communication via a written medium people can take advantage of spell check.
As was already pointed out to you, you have to have some minimal level of education in the English language to use spell check (for instance, you have to know the difference between there, their, and they're).