This is actually exactly how I do music discovery. I create seed playlists with maybe 5-10 songs and start the radio from that. Any songs that I like from the those stations get added to a separate playlist, unless I explicitly decide that I want that song to influence the future selection of songs.

Thumbs-up or thumbs-downing songs in a radio playlist will change the songs that show up, but I find just having a seed playlist is more reliable and repeatable and easier to fine-tune.