I used to be a 100% cash back credit card chaser as it is hassle free and cash is always better than a captive currency like miles.
Recently, I have been reading quite a bit on miles blogs. Apparently, there is strong interest in chasing the miles to redeem for premium flights. But do they actually make sense? The value per miles as advocated by some blogs is 1.9 cents per mile. Hence even paying 2% admin fees to buy miles make sense for some.

I would probably value it at no more than ~1.57 cents, which I will illustrate simply below, base on my personal circumstance.

As I spend 3k per month, I usually split up 2k on UOB one card (5%) cash back and 1k on OCBC 365 cash back card (averages 3.5% or so). For simplicity, the cash back I get back is roughly $135 per month. This