It is true. Nearly 70 years of experience is a sort of treasure to have available.
But also structurally-speaking, to have someone who isn't a political figure available as a source of unity at a tough time is an unsung benefit of a constitutional monarchy. Even if you hate the Prime Minister, there's another unifying institution to rally around.
Of course, it does depend upon the person too. We have had a few that weren't so good. Edward VIII was the last one. Thank goodness Harry was the younger brother - bullet dodged.