Now they can sell you overpriced serial-locked gimped batteries because where else are you going to buy them? I'm not entirely convinced that manufacturers weren't behind this. Who wouldn't want users to have to continually come back to them for replaceable items?
True, this directive can yet become toothless if the available batteries are overpriced and gimped. However they already do it anyway, so at the very least one won't need to take the entire phone apart to change them.
And some manufacturers are already relatively friendlier to battery replacement, so those will probably continue to do so. Apple and the like will surely kick you every step of the way to a new battery, but Nokia or Motorola maybe not.
To make the phones "waterproof" which is funny because even tho phones are water "waterproof" manufactures won't warrenty them out if there's water damage. Doesn't make much sense to me.