To be fair, on most any smoke detector, the test button will verify that the battery is alive and can power the speaker. It won't necessarily verify that the various sensors are operating at their original specifications.

Given that you can buy bulk packs of standard detectors for very reasonable prices, there's very little reason not to follow the fire marshall's ten year replacement recommendation. The obvious analogy is replacing your engine oil on a regular schedule, rather than waiting for something more expensive to go wrong.