If everyone looks similar you don't have to worry about trackers identifying individual sessions. In any case, if implemented correctly, both methods will achieve the same results.
Sure, an incomplete implementation of the randomizing method is less trackable than one of the same fingerprint method, but in practice
* even a non-perfect TBB method will protect you against pretty much all trackers
* and the TBB is, as a matter of fact, not fingerprintable on any of these tracking test sites.
Therefore I think saying that it "doesn't work very well" doesn't quite reflect reality (unless you have a good source on that, I might be mistaken here). And if your threat model requires 100% anonymity (which is an entire level above not being tracked by adtech), the only realistic way to achieve that is to disable JavaScript anyway.
The Tor Browser is designed to be "un-fingerprintable" as well, though instead of randomizing return values it prefers to return the same thing for every user.
Sure, an incomplete implementation of the randomizing method is less trackable than one of the same fingerprint method, but in practice
* even a non-perfect TBB method will protect you against pretty much all trackers
* and the TBB is, as a matter of fact, not fingerprintable on any of these tracking test sites.
Therefore I think saying that it "doesn't work very well" doesn't quite reflect reality (unless you have a good source on that, I might be mistaken here). And if your threat model requires 100% anonymity (which is an entire level above not being tracked by adtech), the only realistic way to achieve that is to disable JavaScript anyway.