I would agree it's a nice program feature to have overall - but the use cases are more narrow than some might imagine. It's basically useful if you have family members who will never earn enough miles to book their own trips, OR you want to book an award trip with everyone on the same PNR instead of booking separate reservations and don't have one account with enough miles.
Outside of those two scenarios (which are mostly applicable to families, rather than just couples), it's generally easier to just use one person's miles or book tickets separately. Even in IRROPS, you can work with the airline to accommodate you together despite being on separate tickets so I find it's usually ok to just book separately.
I will say, I appreciate that they have the restrictions they do (I think it takes up to 24 hours for miles to deposit, there's a waiting period after creating a pool, etc. etc.) because I'd much rather they have those restrictions in place, than allow things to happen too quickly and open the program up to fraud. It just means mileage pooling isn't the right solution if you have a trip you want to book right now, and you already found the flight availability - because once you create a pool and deposit miles, that pricing could be gone.