I have been holding both cards for the free nights mainly, but with the USD so high I am now using them heavily for spending in Japan.

Trying to sort out which card to use is not easy as valuations are tricky, and I am wondering which strategy makes the most sense.

In Japan, Marriott properties require a lot more points compared to IHG, with a Holiday Inn for 10,000 and Crown Plaza for just 20,000. Add in the 4 nights for 3 offer at IHG and it gets even cheaper. On the Marriott side, Moxy/Aloft/Courtyard are around 30,000.

For higher end properties, InterContinentals are 40,000-70,000, similar to W (45-55,000) or St Regis/Ritz Carlton (60,000).

There are the earning choices:
Chase IHG Premier: dining/gas earns 5 points/$1
Chase Marriott Boundless: dining/gas earns 3 points/$1

However, with my titanium/platinum status the rewards are much better than what IHG offers platinums.

Travel the answer is obvious:
IHG Travel 5x (Marriot 2x)

The elite credits ($5000/1 credit) Marriott earns were helpful this year for me to requalify for platinum. Once I got there, I am on the fence in regards to general spending:
IHG 3x
Marriott 2x

There should be promos to get 5x rewards on home improvement, grocery and gas categories until 9/30 on both cards.
For me it makes sense to spend on Marriott card during this promotion. Ymmv.

I didn't realize these still had quarterly promotions. I was going on the spending categories listed as benefits on the Chase site.

I did try plugging in my Chase cards but got this message "not available for the card account you entered"