Which card would you use for Car rental (booked directly or via Costco), not via bank portal?
Looks like CSR was nerfed to only 1x booked direct (8x via portal)?
C1VX 2x
CSP 2x
CIBP 3x
BoA PRE (3.5x as Platinum Honors; 4.2% if redeeming for airfare)
Amex Platty 1x (+ pay for primary car rental ins)
Citi Strata Elite 1.5x
or other?
TY!
You are the king of acronyms, but I can't always figure them all out.
For me this would be a relatively simple calculations: points to be earned (for each option) times the USD value of each point. I realize the value of a point is pretty fuzzy, but I'd use The Points Guy valuations (or your valuation source of choice) – as long as you're getting all the valuations the same place, they (in theory) have relative values that are about as meaningful as can be discerned. And actually, at least according to TPG, all the credit card points (except Wells Fargo) are in a range from like 1.9¢ to 2.2¢ each, so I'd call that a wash.
Obviously the raw number of points isn't the number to compare, it's the value of those points. Bonvoy points are worth a lot less than CSR points, for example. But since the fuzzy values of the credit cards points are all pretty close, it might be easier just to compare them directly.
With the cards I hold, the Citi Strata Elite has become the default card for charges not eligible for bonus multiples, because 1.5x points (and included rental car insurance) beats 1x points with everything else, and the need to pay for insurance with Amex makes it a poor choice for car rentals if you have another option. But given that all of the credit card points are pretty close in value, maybe the C1VX, CSP, or CIBP are better choices.
But another consideration for me would be where I want to accumulate points. It's more trouble than it's worth, really, to accumulate a bunch of points in a bunch of different credit card points programs. I'd rather focus my earning on one program if I can, so that when I want to use CC points to book something, I have enough points to do so all in one place. (Having enough points scattered among different card programs isn't so useful.) But most or all of the cards allow you to pay with part points, part cash, so maybe this isn't such an issue.
It doesn't make sense to be such a points whore that you spend more for a car rental or a hotel just to book it through a travel portal and get bonus points. Unless the price difference is tiny, you'll almost always be better off to book at the place that gives you the best price, using the credit card portal when the difference is zero or near-zero.