I don't think it makes gamers look immature I mean to be honest how many non-gamers know what E3 is? We're not exactly going to get bad press over it. More likely the fact we either have hulking males or well-endowed females appearing in games is more damaging to the industry. Not that that makes it right, to be honest I think gamers would respond more favorably to "booth babes" who knew what they were talking about attractive or not. However I don't see it as degrading or anything.
When I went to the Anime Expo in London there was not a booth babe in sight, so it's not really true that EVERY trade show has booth babes (similarly they were lacking when I was at a Toy expo but seeing as that was targeted at 10 year-olds their presence would have concerned me). Anyway evidently in that instance booth babes were seen as unnecessary despite the fact it was probably targeted at a similar demographic as E3.
When I went to the Anime Expo in London there was not a booth babe in sight, so it's not really true that EVERY trade show has booth babes (similarly they were lacking when I was at a Toy expo but seeing as that was targeted at 10 year-olds their presence would have concerned me). Anyway evidently in that instance booth babes were seen as unnecessary despite the fact it was probably targeted at a similar demographic as E3.