IFR pilots can request whatever they want. ATC will end up giving you whatever they want, though.
When flying to an unfamiliar area that might have dozens of SIDs / STARs, seeing them graphically displayed like this can help filter down to the subset of procedures that are likely to be assigned. Most sites and tools simply present a list of names, and you have to take some action to view each individual procedure to understand what geography they cover. A graphical summary like this makes that paring down to potentially-relevant procedures much easier.