Speed pucks are very cool gadgets.

Using it for training by yourself has very little value.
You have an F16 and those are very obvious when you are going faster or slower. If you had a snipe where adjustments only provided 1/100 of a knot differences instead of 3-4 then I would say a puck might have more value.

To train to race you need time on the water with other boats. Faster is usualy but not alway better if you are not going the right way. Yes you can look at some downloads and see some pointers that might indicate poor technique, but the feedback is delayed and not connected to the events going on at the time.

An hour with 2 boat training is worth 50 with just a puck, and around 52 just by yourself. IMO