There are many situations where this is not good.
1) you could buy this thing buy emus for it. then need the money and sell it.  Then at a later date buy another only to discover you emus don't work on you new one  :angry: 
2)  You could buy it and the emus only to lose/drop/have stolen the unit, again no worky on replacement.
3) You could buy the unit/emus and everything is fine for 3 years.  It wears out or breaks, again no work on replacement.
4) You actually might have two and want to use the emus on either one.  Maybe you want a white one and a black one.
Another example using the Zodiac (Zodiac was BIG on DRM).  You buy a Zodiac load it with DRM locked games/apps etc.  Your unit breaks.  You buy a replacement on eBay.  Tapwave is gone so you can't re-register the apps, you are now fucked out of hundreds of dollars in software that you legally bought, unacceptable.
The point is there are the DRM limits your freedom, I don't like that.  If I buy it I should be able to use it on any unit I like any time.