I've read so many of these threads that I realize it is pointless to continue them, but what the heck...
With any other product you expect to be able to use the product safely and repeatedly to achieve the advertized performance.
If a lamp says it can take "up to a 60 W bulb", you expect to put a 60 W bulb in and leave the lamp on indefinetly without it catching fire.
If a PU truck says it can handle 1/2 ton, you expect to be able to carry 1/2 ton in it repeatedly without it breaking.
If ovenware says it's good for up to 400 degrees, you don't expect it to melt after a few uses at that temp.
If a car says it can do 0-60 in 5.4 secs... no wait, that's different for some reason.