Heads up for anyone that did this deal: apparently the gift card activation handshake between Safeway and Best Buy is known to have a systemic issue, as multiple people are reporting their Best Buy gift cards purchased at Safeway from this deal to be not working. It shows activated on the receipt, but the actual card is not activated (i.e. there is a mismatch between the outer packaging number/barcode and the card inside). Lucky me, I'm 2 for 2 in this problem happening, with the only other time I've bought a Best Buy gift card at Safeway many years ago also having the same exact issue.
Make sure to check your balance: https://www.bestbuy....ft-card-balance
If you got affected by the issue, you will need to call customer service for assistance (Safeway is 1-877-258-2799). There will be a whole rigmarole where they will ask you the gift card number, information on your receipt/activation slip, the number on the outer cardboard packaging, etc. and then you will have to email photos of everything to corroborate.
Unknown ETA as to resolution, so I would strongly advise not to participate in this deal unless you're cool with wasting a bunch of time and stress dealing with customer service.