How much benefit?
It's easy to quantify: today's rate for supercharging, assuming no referrals, is $.28 per kWh. In a pre-Raven Model X, it's 2.95 miles per kWh or 9.5 cents per mile - the absolute maximum value of FUSC.
That means if every single mile was consumed from supercharged stations (which was never Tesla's intent BTW), at 12k miles per year, we are talking $1,138 per year or around $100 / month.
Most off-peak rate utilities charge around 12 cents per kWh (some less, some more), so home charging (which is what Tesla strongly recommends BTW) is $488 per year or $40 / month.
To me, home charging is a no-brainer, not because of the cost but the time -- I save countless hours each month not pulling off the road, waiting for a supercharger, waiting for the charge, etc. So home charging, even with Tesla's excellent $500 wall connector, is the biggest bargain of all - both in absolute and opportunity cost. You could even say home charging is like getting "Half Off Supercharging."
Regardless, for me personally, there's no way I would buy a lesser car simply to get FUSC. You can save more money simply clipping coupons each week.