suppose you have a point! all depends what you start with and what you decide to use, of course if the rolling radius is the same then that issue wouldnt arise! just going from when i bought an wheel and tyre package years ago i had the issue of the geometry being out.
if you did start off with say 14" wheels they must have a massive tyre wall compared with say anni bbs wheels.. i would have thought the rolling radius of golf 1.4 wheels and anni wheels would be totally different?. so, say you had a 1.4, lowered it, then decided you wanted anni wheels, what size tyre would you use then as the aspet ratio of anni wheels is already low.
then of course you would have to sort your speedo out via vag-com.