One of the dreariest and most familiar of stories in philanthropy is that of the sound and good person of wealth who leaves his fortune to a foundation, only to have that foundation after his death depart on adventures he probably would have opposed and certainly would not have supported. (Ford, Rockefeller, MacArthur, to name a few.) A choice temptation is to use foundation dollars to campaign for government dollars.
Community Foundations have a better reputation and record. State Representative (and Discovery's director for the Chapman Fellows in Civic Leadership) writes in Philanthropy Daily about the 100th Anniversary of community foundations.
There is less mission creep among community foundations than among foundations in general, though the temptations are always there. Regardless, many towns and states are decidedly better off for their devotions.