Features like Bluetooth audio add value to products, so they raise the price of BT-equipped gear. I don't have a problem with that, but I'm surprised how much sound quality people are willing to give up just to have wireless audio.
Cheap Bluetooth add-ons like the $25 Belkin Bluetooth Music Receiver or the $40 Logitech Wireless Speaker Adapter can stream tunes from a smartphone, iPod Touch, iPad, or other tablets sans wires. That's nice, but the processing sounds awful -- gritty harsh, limits bass oomph, and has unpleasant treble -- compared with just running a wire to the device. Great, BT puts music choices at your fingertips, but if that's the main attraction, why not just run a $3.37 wire 25 feet from the device to the amplifier or speakers. If running wires isn't possible, you could walk over to the device and select your music. Think of it as a low-impact aerobic activity.
I just trashed the sound of BT on the cheap, but even when it's used in higher-end gear like the $699 NAD Viso 1 iPod speaker, BT doesn't sound as good as a direct connection. The Viso 1 uses higher-fidelity Apt-X wireless technology, so it definitely sounds a little better, but reception isn't robust and the BT signal would occasionally sputter and drop out if I walked in front of the VISO 1, or put my hand over the front of the device. Direct docking sounds better.
BT for battery-powered speakers is another matter; their inherent sound quality limitations are usually greater than BT's, so you might as well go BT with portable speakers. I suppose BT is adequate for sending background music around your home, but BT is less good for people who actually listen to music, and if you do, my advice is simple enough: if you care more about sound quality than convenience, use wired connections.