Well, the ERS is better than the FRS in the same way and measure that the FRS is better than the BRS, right? Let's use the CPF LIFE Estimator for reference and with these assumptions: male, born in 1968 (age 55 now), Standard Plan. OK, here we go with the projected monthly payout amounts at age 65:
BRS: $850
FRS: $1,600 (+$750)
ERS: $2,360 (+$760)
I think there's a rounding "error" in there since the CPF LIFE Estimator evidently rounds to the nearest $10 increment, but the basic point is that BRS→FRS (+$99,400 in your RA at age 55) increases your age 65 CPF LIFE monthly payout (Standard Plan) by about $750. And then adding another $99,400 increases your payout by the same increment. So that +$99.4K is equally productive whether you're going from the BRS to FRS or from the FRS to the ERS. More generally, every dollar above minimum mandatory is equally productive.
Anyway, if you think the "upgrade" to FRS (which is voluntary for anybody with a house, really) is a good enough deal then further upgrades, up as a high as the ERS if you wish, are exactly the same deal. Since my household's view is that the FRS is a good deal then we logically view the ERS as also a good deal (since it's the same deal, with equal productivity). And since we're fortunate that we can easily afford the ERS(*) we're taking the deal. One spouse already has, and the other plans to.
(*) And this is really the key. If you can't afford the ERS, or FRS+25% (for example), OK then. You stop at some point below the ERS. But the FRS is merely a default, not an obligation. You can go lower or higher. You should go higher if you can afford it and if you view the BRS to FRS increment as a good deal.