Radio good for discovery
Radio is good for discovering music precisely because it's someone else's choice. If you're just searching on Youtube then 99% of what you hear is your own choice, therefore you're unlikely to hear anything new.
As for 'recommendations', a lot of the time people are reluctant/too busy etc to actually listen to something new, whereas on the radio you're almost forced to. The tradeoff is of course having to listen to several hours of godawful shite* to hear one good track (on average).
*in one's opinion, YMMV