I don't think Virgin is out of its mind, but a little research on your part before buying, may have paid dividends.

M+M fares are classed as a reward redemption. Redemption flights on any arline won't earn miles.

The fares are there in order that non-frequent fliers, who will probably never earn sufficient points to get a decent reward, can use their miles to save a bit of money.

I must admit, this is the first time I have ever heard of anyone converting points from another scheme in order to buy them.

Nick