Much better than nothing, assuming your track has a timer.
I tested on a 30' track for a couple of years.
Every time I raced, I created a ratio between my own track and the PWDRL track.
That way I at least knew on the next race approx what time I would be, and at what place.
Now I have a 40' track, which is obviously better, but you can still find a lot of errors on 25'