There is a chance that the oil might come down in price.
I heard that Chateau Petrus was thinking of supplying it.

Most BMW dealers will do a deal on pre-purchase of oil - whereby you pay for the bulk purchase for the next three years’ servicing.
Of course - this ties you in to a particiular dealer, but if that fits your plan...... it is a better return than keeping the money in a bank account etc.
Conversely - it is another ploy to get people to add it to their PCP contract.