You need to get rid of the concept that some vapes eat your weed up without providing much vapor while others give you twice as much from the same amount. Conservation/efficiency is 99% up to the user, not the vape. What different models/designs do is encourage or discourage efficiency. A log vape with a narrow diameter air path and small bowl, will not provide big hits, so if that's all you use to vape with, you'll use a lot less than you would with a big hitter. Can you use the same amounts in both types? Yes, but the reality is that you won't keep loading up that small bowl over and over again in order to use .1g in one session. You'll say 'Fuck it. I'm high enough'. You also won't load a very small amount (like .03g) in a big hitting vape. You might try it, but you'll end up saying 'Fuck it. I can't even tell if I'm getting a hit'. If you wait for the effect, you'll know you got a hit, but nevertheless, people don't want to use a big hitting vape with really small amounts. It's not enjoyable. And using a miserly vape all the time, that restricts your hit size, can also get frustrating for a lot of people who know what an effect a huge vapor hit can have. This is why so many people choose to use both a big hitter and a vape that helps you conserve your supply and control your tolerance.
Everyone is different. I rarely use .1g in a whole day, let alone one session. I enjoy a huge hit as much as the next vaporist, just not as many per session/day as some.