According to AwardWallet, Virgin Atlantic will join the SkyTeam alliance on March 2. In fact, as early as 2022, they had already announced that they would complete joining SkyTeam in early 2023, and Delta holds a 49% stake in Virgin Atlantic.

After joining, the main benefits will be reciprocal mileage earning, the ability to redeem award tickets across the alliance and on multi-airline itineraries, plus some reciprocity for elite status benefits and lounge access. In fact, you can already use VS miles to book Delta flights, and the value is very good. Hopefully these sweet spots will survive after the integration, instead of moving to Delta-style dynamic pricing.