Interesting. Would love to hear why.
Insignificant? Maybe for highly liquid securities which may have a 1-2 cent spread. Irrelevant? Unless the spread is zero, I don't think so.
I have sold at the ask price and bought at the bid price plenty of times, when the prices have been stable enough to actually tell. A simple limit order at the appropriate price allows you to wait for buyers or sellers to come to you.