I'm not sure I would go that far on the warranties... depending on the device, some I've come to use rather frequently.
Up until they changed their policy regarding handhelds and consoles, it was a boon for consoles, especially the Nintendo DS. Also used it with the Xbox 360, to allow me to have the model I have now. And thanks to my rather rotten luck with bluetooth earpieces, same deal there.
If it's something you expect to be using every day and want working, and depending on the terms, it can be worth your time. If ever something does
go wrong, at least you can exchange quickly, which is a plus.--
Because, f*ck Sony