I use my autostick constantly while driving. I use it a lot to help slow down (curves or at a stop light). This helps reduce the brake wear (and dust on the wheels). Having it in 1st gear shouldn't change your acceleration whatsoever. However, you are only going to go so fast in 1st.

Downshifting while on curves or getting on the highway will help keep your engine at an optimal RPM range for acceleration/braking. My suggestion is to play with the autostick more as you drive and you will get the hang of how it works.