The problem with the so-called "Canbus" LEDs is that (I believe) they "solve" the problem of the car detecting low current and hence fast blinking by wasting a bunch of power, so the car can't tell that there isn't a filament bulb there.
But that wasted power obviates a lot of the reason that I'd want to replace the bulbs with LEDs (i.e. greater efficiency). Yes, you still get the greater longevity, although all the wasted power causes temperature rise, which will reduce life. In an indicator this would usually not be a problem, however.
Note the (space for?) 5 resistors directly across the terminals to waste power:
If I'm wrong here, I'd appreciate a technical lesson. But these things seem to have to be cheap, so there isn't room in the budget (and often mechanically too) for anything sophisticated.
I wish cars would come with a LED option, that reduces the current threshold for the fast blinking. That way, you'd get all the benefits of the LEDs, and most users who don't care about LEDs don't have to pay extra for the LED bulbs. Maybe the problem is that many third party LEDs will have different current draws, so that you would not be able to alert the driver to a faulty LED if just one of them blew.
