Giants are definitely favored here. Many many very good L7 bar routines with giants. Typically we will have bar scores easily ranging into the 9.6s here at states, and one year I had a former teammate get 4th place with a 9.8. If you have relatively young girls, they better be working bars if they want a chance to compete at this level. Even in smaller meets you aren't going to get a 9 without cast handstands, giants or a circling skill that actually hits handstand. There are many reasons for this (one being that the girls who have these skills tend to be inherently better) but it's been this way since I've been a L7. No matter what the official requirements say, routines without these skills simply don't score that well and aren't competitive. If it's the one thing holding them back, a tight routine without them that meets the requirements may get high enough scores to contribute to the AA score. I'm not a fan of inflexible "extra skill requirements" either.
But giants are a pretty standard L7 skill to me. Even when I was a L7, we were starting to see that top routines had a free hip handstand as well as giants. There are so many routines that have them now, with decent form, that routines lacking the amplitude of either of these elements just aren't going to cut it. If a gym wants a competitive L7 squad, they are going to require or strongly push giants. Having traveled, spoken to people, etc, it doesn't seem like very many places are that different in this respect. My general operating assumption at this point certainly is competitive L7 routine=giants/circling skill through handstand.
Also, as far as "a lot of work for little gain in value" certainly if the gymnast can safely perform these skills, much less with excellent form, there is no question in my mind what they are going to do. If they wish to progress through optionals it is very important that they start building the endurance, competitive experience warming up more difficult and a wider variety of skills, and getting very comfortable with these BASICS. Actually I would say it is completely counterintuitive to the point of competitive gymnastics to call anything done well "a lot of work for little value". Of course it's a lot of work - gymnastics always is if you plan to progress. I'm confused as to what else could be expected. At a state meet under L8 here, .3 can easily be the difference between 1st and 10th or even more (after that things go through a major bottle neck). More amplitude and better form is ALWAYS worth the work. My old coach regularly encourages her 6s and even some 5s to cast to handstand in their routines even at the risk of "going over" - she would rather see them go for the handstand and possibly fall at those levels than play it safe with a small cast. By late in the season, those who are capable of it are often showing a lot of confidence and control on these skills - they learn by the experience of doing it. It's a process, not just one meet where they might have gotten a better score with a lower cast.