7.5k spend on flights is not at all a trivial amount of money for all but the wealthiest of self funded travellers. It's slightly more palatable given the BAH system, but even then £7.5k per person is still a lot to spend on holidays for the vast majority of families, and even for couples/individuals without children.

For a family of 4 you'd have to spend £30k a year on holidays to hit that due to the way it's divided up. £20k if you're getting the CC cap (but that would mean only one member of the family gets silver, unless both parents have the card and each spend the expected £25k to hit the cap. If not, the others would be bronze so not everyone can even use the lounges), but even that is a lot of money, and is absolutely not trivial in any sense of the word.

And even that requires all holiday spending to be done through BAH, screw you if you want to collect hotel status, go to a destination not offered by BAH, or stay in a hotel which isn't in their selection.