FWIW, I just sent my SO on a Turkey Day run from SEA to OGG and back (same day return) for about $400 so they could re-qualify for NWA Silver.

Why?

1) Reasonable upgrade chance on NW, but that's not the primary reason
2) 50% bonus miles - good reason
3) Elite benefits at ST partners and AS - a very good reason
4) Elite seating, including exit rows on DL and AS - an extremely good reason
5) Elite Security Lane access - another extremely good reason

Upgrades are great, but there are other benefits which come with even first tier status, as I listed above. Most people will assign different personal values to these benefits, but in our case, it was well worthwhile.

Next year they will spread the flying out more so a last minute unintended run won't be necessary.