From a story perspective, it adds a touch of sadness if Peter and Gwen never consummated their relationship. It adds adds to the layers that already exist...i.e. Gwen died without knowing Peter was Spider-Man, without gaining catharsis for her father's death, being unconscious at the moment of her death...so that meant that she died without knowing she was going to die, which is part of the reason why her death is so cruel in its staging. So it's sad on many levels.
When Lee wrote Spider-Man in the '60s, he was still part of industry self-censorship but he was also personally old fashioned himself and wouldn't have been comfortable exploring sexuality in an all-ages comic (it took Chris Claremont in the X-Men titles to really start dealing with that). So for instance Peter's relationship with Gwen is framed in a very stodgy old-fashioned way, i.e. Peter has to prove himself worthy of Gwen's affections to her father Captain George. The first kiss that Peter and Gwen had on page was ASM#59 and in the panel of their first kiss, George Stacy looks on and approves as a cheerleader. That doesn't make sense today of course, and obviously a modern writer if he figures that Peter's college era now happened in say the late 2000s-2010s because comic book time has come forward would assume that Peter and Gwen did get it on. Of course, they would also assume that Peter and Betty Brant got it on, and think that Betty was Peter's first.
More important is the issue of space, if Peter and Gwen got it on, where did they do it? Gwen lived with her father. Peter stayed with Harry Osborn in his loft, and he hardly had much free time to use his bachelor pad...and likewise Harry was a pretty terrible roommate all things considered, so I wonder if Peter and Gwen would feel comfortable using his room. It makes less sense with Betty, because while she had an apartment and a place to stay, Peter stayed at Forest Hills during the entire time in the L-D era. One of things about Conway's run is that it was the first time Peter finally got an apartment all to himself at a place down in Chelsea (at the time code for cheap rat-infested apartments...today gentrified as all-get-out). So that meant he had a place to bring girls home at last, which he did at the end of ASM#149 and later on with Felicia.