I think the holodeck's improvements were just a number of ones to make the experience that much more real. Wondering why Picard is raving about the experience, IMO, is sort of like wondering why a person raves about the quality of the picture on their new HDTV set. I mean, did he have no form of visual entertainment before?
The "upgrade" could've just made the experience "more real" with better visuals, better sounds, better smells, and better manipulation of space (more precisely the perception of depth on the holodeck walls.)
Beverly's unfamiliarity with 20th century clothing and such is odd too, I mean she really thinks and an inedible lump of flavorful of rubber is meant to be swallowed right away after a couple of chews? Is she that stupid? (Don't answer that.) We also plenty of times in the series still see women wearing high-heels and make-up so both should be familiar to Beverly making her
infamiliarity with them that much sillier.
In a 4th (?) season episode "Clues" we get a similar unfamiliarity with 20th century stuff when Guinan expresses confusion over how to work a pair of nylons and a garter. First of all we know that tights and hosery still exists in the 24th century as women still wear them and I think that "you put these-leg shaped things on your legs and then use these clips to hold them up" would be something that someone could figure out easily enough without looking it up on the 24th Century version of Wikipedia. (As Gunian likely did in her process of figuring out how to use them

.)
TBG I still find to be a fun diversion episode, however, and wish it had focused more on the "adventure" in the holodeck than the diversion of the meeting with the insectian aliens which was just a "throw that plot in there for the fuck of it!" diversion. And, oh, yeah let the inexperienced kid mess around with the machine that can
vaporize key members of your crew! Great idea!