Spray foam is not that good. FYI, there are cases where roofs had to be removed because of improper application. It needs to be mixed correctly and cure properly. Don’t be naive and think about the consequences.
Maybe northeasterns have a lower soil or they’re prone to flood or heavy rain. Sump pumps doesn’t mean water issues or molds. I think it is a proactive reason, also, it helps keep their basement dry.