chain and sprockets - dropping/raising teeth?

[Ian-man]

You have the wrong idea.
Yes in top gear the revs are higher for a given speed but thats not the reason for the change.
Changing the gear ratio lowers the effort required to push the bike along so increases the acceleration at lower revs and lower gears. This gives better acceleration with the negative effect of higher revs at motorway speeds and poorer mpg.
It depends what you want to do with your bike. Cruise about or blast up and down the twisties.