I had a teacher (also from Karma Kagyu) who would use a racecar metaphor: the point of a racecar is to be a really fast vehicle. That doesn't mean that a racecar is the most suitable vehicle for all tasks, or "best" in any overall sense of the word. Racecars are only well suited to certain conditions, and are usually driven by people who trained and practiced specially to drive them. Some tasks and lifecycles need a pickup truck, others a minivan, others an 18-wheeler, and personally I love to point out that the bicycle is the most efficient form of wheeled transportation.

So anyways the vajryana is the racecar. The point of that metaphor wasn't to flesh out which schools corresponded to a sedan or anything, but more like to point out how few people drive racecars, how few tasks or challenges are well solved by racecars, how much training, respect, and caution you might want to have before you started driving racecars at full speed, the conditions under which you would consider driving a racecar, etc. etc. And like you said, there's no judgement for not driving a racecar -- if anything there's a lot of respect and/or demand for people to drive more practical vehicles.

tho idk, personally, even though in my material life I prefer a bicycle, in my spiritual life I'm still trying to train to drive the racecar, so maybe it needs an even less sexy anology.