I'm trying some right now. I patched in my 706's audio into an unused 3pc set left over from a Dell desktop. Has two slender desktop units and floor sitting woofer. Not quite like listening to "Out of Eden" by the Eagles but sure beats the little 2.5" inside my 706!
With that being said I don't plan to continue. I think the best alternative is a larger diameter external speaker.
I use a pair of Berhinger MS40 amplified speakers for all audio in my shack. Each rig and computer is run into a Behringer mixer panel and the output from that goes to the speakers. I have been playing the "speaker" game for fifty years and this is the best yet. The biggest drawback with computer speakers is keeping the RF out of the audio line. The Behringer line has been no trouble at all for RF problems.
I'd just add a better speaker. For basic communication, my favorite is a Motorola "Motrac" style speaker with the original speaker replaced with a dual-cone, available at most WalMarts. Next step up is a 6x9 car radio speaker, mounted in a nice box.
Computer speakers have an amplifier that can easily be overdriven by most audio output stages. IMHO, the satellite tweeters on most systems are very much lacking in overall response, which is made up by the main unit/subwoofer; the internal amplifier may have equalization built-in to overcome the speaker driver limitations.
Sounds like an analogy to using the car's audio system for speakers. Guess it depends on what you want to hear. I prefer a powerful, wide-range amp/speaker combo -- but others prefer communications-tailored audio. I say try 'em all and decide what you like to hear best.