Peteski: IPA is usually only alcohol and water. Denatured alcohol may have other stuff as well, depending on the denaturing method, and one doesn't always know what it is. Some would work just as well as IPA for a particular job, another brand might not.
Then there's rubbing alcohol, another matter entirely. We used IPA (as "isopropanol anhydrous") for cleaning tape drives and checker reader/sorter read heads for decades. Once, in the early 80s, we ran out, and an operator bought rubbing alcohol as a substitute. It was a lot of work to get the hand lotion, or whatever it was, off the read heads!