Miles Booster - seems worth it?

Have been looking at the new Miles Booster section of the VS website. Having taken 2 flights to NYC in March and July these both in the 6 month window for claiming miles.
If I boost and double miles = 13,832 + 1000 bonus @ £138.32 x2
= 29,664 miles @ £276.64
I've never bought miles before - it's always seemed pretty expensive as I earn plenty with my black Amex card but this seems pretty good.
Currently on the VS website 30,000 miles would cost me £465! :0
Anyone else think this good value?
If I boost and double miles = 13,832 + 1000 bonus @ £138.32 x2
= 29,664 miles @ £276.64
I've never bought miles before - it's always seemed pretty expensive as I earn plenty with my black Amex card but this seems pretty good.
Currently on the VS website 30,000 miles would cost me £465! :0
Anyone else think this good value?