These are used in busy airspace primarily in the California and NY
Just as a point of information, they are not the same in the northeast as in California. From an EFB standpoint the biggest difference is the northeast ones are not coded by name, so you don't ask for them by name and there's nothing to retrieve from the database.
But for the California ones, at least being able to put the in a flight plan "shorthand" would be a benefit. In the two EFBs I've looked at which support it, neither list them in procedures, one does allow loading by name, and in both they come up when you use their common route advisor functionality.