As a long-time cyclist and former bike courier, I think most of the proximity concerns are probably of my own doing. I wonder if the device somehow accounts for this.
My initial reaction is that an accelerometer might be a better data-point, or combining this with accelerometer data.
I'm working on the assumption that a smoother path means I am interacting less with traffic or other hazards.
Given a choice between a street where the cars are stuck in 2km/hr traffic and I'm passing them with a less than foot (0.3m) gap, or a street with 70km/hr traffic where they're passing me with a 1 meter (3 foot) gap... the former feels a lot safer.
Admittedly these streets aren't usually close together (either in time or space), but I've certainly biked on both.
Still, imperfect data can be better than no data.
I wonder if this can be predicted by a heat map of car crashes in your area. This is based on my private hunch that car crashes are a predictor of bike crashes. After all, if a car can crash into another car, or a stationary object such as a tree or a building, then it can crash into another bike. And the causes may be similar: Speed and inattention.
On such a map for my locale, the most crash-prone roads are exactly the ones that I instinctively avoid.
One potential issue with counting is that crashes aren't created equal. To reference back to the extremes I discussed above, if I crash when I'm going 5km/h and it's going 2km/h... it's fine*. If I crash going 30km/h with a car going 70km/h I likely have life altering injuries (or am dead, though I believe the statistics say I'm actually pretty likely to survive a collision at that speed differential).
I.e. fender benders between cars (and between cars and bikes, I assume) are common, but not really what we care about.
Not to say it wouldn't be an interesting map to make.
* I've never been involved in a collision, but I assume I'd be fine at these speeds and any damage minimal.
I’m not sure how much that matters. You won’t need to initiate close passes as often on a safer street.