Well as for eligibility, I was not really meeting the Infinia criteria, but the CC person was pretty confident he could get me Infinia (Metal, non-LTF) without too much worries.
At that point, probably I wasn't really thinking very mathematically. But to justify the cost of Infinia, one doesn't necessarily need to spend a lot. The way I think about it, Infinia costs around 4k to 5k (joining fee + GST - value of points). At 3.3% rate (versus my LTF Regalia's 1.3% rate, so 2% higher reward rate on Infinia), to break even the 5k cost, you need to spend 2.5L on the card. My spends are close to 25k per month + 15k rent. Maybe an odd intnl trip a year, that would add another 3L to 5L.
So no, I don't really have high spending on my card. Hence, applying Infinia directly would have been a better option vs in my case now they additionally have the "7.5L spend in 6 months" criteria for the upgrade, which I definitely won't reach.