Backflips do not get technical scores. They are not "listed elements" in the scale of values.
They can be included in choreo sequences, where they can add to the grade of execution if they enhance the sequence, according to the bullet points
@dorispulaski posted above.
They can now be included in step sequences, e.g., in the short program where there is no choreo sequence. But they don't add to the technical level, so the only rewards would be in GOE or PCS.
They could also be performed as isolated or transitional moves between elements, in which case they could be rewarded in PCS if it enhances the program as a whole.
But those rewards are for each judge to determine for themselves: Did it enhance enough for me to reward in GOE and/or PCS? Did it detract enough for me to penalize? Was it irrelevant to my evaluation of the scores? YMMV.
We can ask the same questions about a number of other elements that were previously illegal or discouraged and are now popular and rewarded. Or in some cases even required (e.g., not-touching step sequences in ice dance).
For singles skating, things like knee slides/knee turns, hydroblading or cantilevers with a hand on the ice, as well as other aerial moves like "raspberry twist" or "540" jumps that skaters had been including in step sequences and choreo sequences. Cartwheels and similar moves used as "difficult entrance/exit" from spins (which can count as a level feature) as well as within sequences or as isolated moves.
Many of these moves do not involve blade-to-ice skills at all, or not primarily. Do they make programs better? Depends how the skater executes it and incorporates it into a particular program. So for PCS they would not likely help the Skating Skills component but certainly could meet Composition and Presentation criteria.
IMO some enhance, some detract, and some are meh. But the mere fact of including these moves is no longer rare or creative. Or transgressive, which in itself aside from quality used to be a positive for many fans and a negative for many judges.
All these things expand the repertoire of available moves on the ice, which can make things more exciting when skaters are able to move in a wider variety of ways on the ice. E.g., my brother-in-law was particularly taken with Aymoz's SP in the team event because of all the low-to-the-ice moves.
In pairs, we've had carry features in lifts as a way to increase the level for quite a few years now, after non-rotating lifts being illegal for decades.
In ice dance, in addition to the required side-by-side skills that would have been illegal decades ago when separations were strictly limited, there are now explicit choreographic sliding, hydroblading, spinning, lifting, and assisted jumping moves that are not individually required but teams (and solo dancers) need to do
some choreographic/non-leveled elements now to earn maximum points in their free dances.
Again, do these moves make free dances more exciting? Do they detract? Depends how well they're executed, how well they're integrated into the choreography, and how each judge or each fan feels about that kind of move or about being purists to what ice dance was decades ago. We won't all agree.