Have I got the maths right? Just realised that for anyone with an HSBC Visa Signature card, the extra 3X Rewardcash for all the Red Hot Rewards spending categories works out to 1 mile per $4.17? Presumably this means that it's better to use Visa Signature rather than BEA Flyerworld (1 mile per $5) in all the numerous spending categories covered by Red Hot Rewards (dining, home, entertainment, etc)? Rather than onlly using Visa Signature in whichever one of these spending categories you've chosen for your 5X rewards?