I never would have known Deltan pheromones were a thing if I hadn't read promotional material and the novelisation (my first viewing was SLV on TV) so I just thought Sulu was bamboozled by a pretty face. Later on though, we see that Ilia's mere touch does funky things to Chekov. So while at age 10 I may not have understood the full context, I got the general gist that Ilia wasn't really supposed to touch humans.You can tell from the context of the scene in Star Wars that the Kessel Run is some sort of measure of speed or a regular trading route. In TMP, it's "She's... Deltan," some hemming and hawing with no context whatsoever, and then Ilia saying, "My oath of celibacy is on record, Captain," out of nowhere. You get the idea that the oath of celibacy is important somehow, but there's never an indication as to how or why.
I actually read the TWOK novelisation before TMP and the Deltans in that were awesome.