Let’s put it this way. The more (and earlier) you fund your future CPF Retirement Account via top ups and transfers, the more liquid dollars you’ll likely find in your Ordinary Account on your 55th birthday. Or, if you don’t meet the FRS on your 55th birthday, the easier and faster it’ll be to meet the FRS after 55.
Also, once your MA reaches the Basic Healthcare Sum, and your SA reaches the Full Retirement Sum, more dollars flow into your OA from compulsory contributions. You can use OA dollars for housing and/or for the CPF Investment Scheme even before age 55. Your MA reaches the BHS faster if you make a Voluntary Contribution to MA. Your SA reaches the FRS faster if you top it up with cash and/or OA dollars.
On top of all that, if your SA reaches the Full Retirement Sum faster, your other retirement savings — you are saving for retirement above CPF savings, right? — can be safely reduced by a similar amount while still meeting your desired retirement objectives.
In short, good things happen when you add funds to your MA and SA (and later your RA). Especially, but not only, when you enjoy some tax relief.