Earlier quoted context omitted.
This is an overly simplistic view of options trading. Let’s say I had a view that the stock was going to be volatile, more so than options implied, but didn’t have a directional view. I could buy the calls and short the stock and scalp my gamma during the move. Or let’s say I was short the stock and wanted to hedge during a volatile FOMC period.
How exactly are you scalping gamma by buying calls 24 hours before expiration?
In the above, I’ve just realized a small profit by trading the underlying and a small bit of theta burn. As long as the former is greater than the latter (as long as realized vol > implied vol) I make money.
Rinse and repeat this process over and over again.