So the question is, is it worth to go to extreme which opt for BRS and with fully paid hdb, only need to transfer $46,500 to purchase the CPF life. The rest just keep in the SA account to earn 4% interest with the freedom to withdraw anytime.
Where are you getting the $46,500 figure from?
For members who turn 55 in 2021, their Basic Retirement Sum (BRS), Full Retirement Sum (FRS) and Enhanced Retirement Sum (ERS) are $93,000, $186,000 and $279,000 respectively.
$46,500 appears to be half of $93,000, i.e. half of the BRS.
"SA shielding" obviously has merit as you cross your 55th birthday, but there are some limitations with SA:
1. Once you reach the Full Retirement Sum or age 55, whichever comes first, you're not allowed to deposit cash into your SA in a directed fashion.
2. Age 55+ withdrawals come from SA first, then OA. OA earns 2.5% interest. As you withdraw funds you tend to drive down the "blended" interest rate across SA+OA. (And I really view SA+OA as a single "bucket" from age 55+.)
So it's not as if you're often going to be deciding between SA and RA except perhaps when you "shield" SA across your 55th birthday. Instead I would look at it from the point of view of whether putting cash into RA (or cross-spousal OA to RA deposits) is a good deal, because that's one of the few deals on offer from CPF once you hit 55. And the answer is an emphatic yes, it's a good deal. If you've got cash lying about, and if you maintain enough liquidity (CPF SA+OA helps), then pushing money into RA and/or MA can be a very wise decision.