I am not with Velocity and buy fuel weekly at BP. 4,500 points will give me a $25.00 BP gift card. That means I will need 2,250 litres at $1.50 per litre for 98 Octane costing $3,375.00 to obtain a $25.00 fuel card. A 0.74% discount, not even 1%. This is a joke. Why should I receive the same number of points for 98 Octane as someone buying regular unleaded at18cents per litre cheaper? 3 points for 98 Octane might make it worth it. BTW, the BP Premium used to be only 12cents over unleaded! Just another example of a company paying cheaply to track your spending habits. Don't join until they improve the offer is my recommendation.
I think it varies for everyone. In your example, your loyalty is already with BP and you still buy 98 fuel despite the increase in premium fuel over regular fuel.
The value to some lies in the accumulated addition of all the small opportunities to collect points. Like Fuel, Credit cards, mobiles, hire cars, etc etc
If one was only price conscious they would buy for example a Woolworths Gift Card at 5% discount on the Platinum amex credit card and buy fuel at woolworths petrol and use a $0.04 discount voucher..