I've never so heard so much crap spoken on 121.5 as in the UK at the moment - I'm not past there often but have heard numerous weekend warriors bleating that they're "unsure of our position" - trollip! Learn to nav or buy a hundred buck GPS. 121.5 is for emergencies - keep it that way.
Without a "practice" frequency as on UHF to keep 243 free, 121.5 is rightly used by PPLs unsure of their position, if not in contact with another unit. We all started learning to nav somewhere...