[carnut169]

Well... it is expensive, but....

If you raced SCCA events most are 15-25 laps.

Think about the advantage this device could give you in qualifying... Knowing your competitors times before the results come out!
You could do a hot lap, pull into the pits and see if your time is good enough. If not, you go back out knowing exactly what time you need.
Or during the race... are you gaing on the guy in front or is the guy behind you closing the gap.

The other advantage is that quite often the time your timing system gives you is different from what the track says. This device tells you exactly what the track is looking at.

If you want logging get a data system- AIM is fantastic for the $$.
Lap times are fine but rather weak when it comes to looking at ways to improve.
A basic logger will tell you times based on track segments- shows you where you need to improve.
It will also show speeds, g's, times, all on a map, again divided into segments.
Upgrades can tell you throttle position (you thought you had it floored, but really did not) brake input, steering wheel input (are you sawing the wheel?), and so much more.