It's actually approximately as efficient via Love Gems to tier with Hard as it is to tier with Expert in Score Matches and Token Events - moreso if you can't get S or maybe A rank in EX. It just takes more time. Basically I just didn't tier until I had leveled up to be able to use only about as many Love Gems as I get as rewards during the event - eventually, you get such a high level (and thus such a huge LP bar) that you can actually get more Love Gems than it takes to tier. And early on, the unidolized version you get without tiering is enough to pump up your teams enough while you're still leveling.

...And also if I don't like a card's idolized version I don't bother to tier for it. And I've only pulled three or four times in a year (though that's partially because I'm saving for the New Years set).