I'm guessing this will only be useful for certain types of users. There are two real theft goals: either the thief is after the computer or after the data. I don't have the numbers, but I suspect the thief is after the computer (to sell on eBay, etc.) 95%+ of the time. Assuming this does actually make the computer inoperable, the thief will simply throw it out when it stops working (you won't get your computer/data back, and he doesn't care what was on the disk).
If the thief needed to retrieve data from a laptop, the first thing an intelligent thief (say, a competitor company) would do is take out the hard disk without turning the stolen machine on and put it in a separate machine. This kind of defeats the purpose of a remote lockdown, because as far as I can tell, it requires that the notebook must be powered on. It may or may not be encrypted, but most people don't use full-disk encryption, so they get what they're after. So, this might offer a slightly higher degree of security against the first type of criminal, who is primarily after the laptop, but not the second, who is after the data (which is presumably much more valuable).