An additional option to play a Musicblock that is on the ground would be grand. Play for is unnecessary in this case, and should not be an option for a block being accessed from the ground.
Only trouble with this is the potential for noise pollution -- imagine being spammed by multiple music blocks as you're trying to go about your business.
However, what about this: an entertainment center/jukebox/music block stand item of furniture, to enable "performances" in houses and towers?
I would love to be able to play music without having to put it in my inventory, that's for sure. But Annuska, there may be hope for your jukebox idea. People who are collecting them for trophies and such end up with a lot of musicblocks (or radios, as I call them). The jukebox could be furniture, that holds only radios, and when you interact, it plays one you haven't heard today, for iMG. It's kinda tedious to interact with every radio every day. A jukebox could streamline this while I'm out back crafting or something. It could keep playing new songs until you told it to quiet down. It's a neat idea. In the very least though, being able to use items that aren't in my inventory would be grand. It'd save so much space...
I would love a jukebox to put in a tower cafe/bar with the ability to plug in whatever music boxes I have collected then someone could come along and play whatever for a number of currants.