I used to get my status cards as soon as they updated on CO
This is CO systems we are talking about, so what UA did before does not matter
I agree they should send cards as soon as status changes like DL as that is better than waiting for Jan 1
For partners, they may need to see the actual card for the benefits, so better to have any card in your hand
I had my physical card swiped once in MAA for a 4th bag on LH (LH F =3 & *A G 1 extra)
And in Cairo, waiting on a EgyptAir flight to Luxor, we tried to guest us in and got our cards closely examined with 4 phone calls for a half hour of a better chair and free fruit juice.