Yes, that's how the Alto's works. You arrange your fabric on the mat, line it up on the mat lines, and use your rotary cutter to cut through your fabric on the lines, using the heavy plastic ruler that you move from place to place depending on the size and shape of the pieces you want to cut. One of the best features of the system is that you can cut multiple layers of fabric at once but this does require a fair amount of strength using a rotary cutter. So if you have problems generally with doing rotary cutting, I would think that you wouldn't be happy with the Alto's.
There are probably demonstrations on the internet of the Alto's that you might want to watch to see how it works exactly. It's kind of hard to explain.
(I do also agree that fabric pieces cut on the Alto's can end up not quite exactly the right size due to some slippage , especially when trying to cut multiple layers. I don't know that there's any way to avoid this. I expect the Accuquilt is more exact in terms of producing the precise size pieces repeatedly.)
Danade