Or so I surmise . FYI I created this thread as a spinoff of this one.
But given what we know about Hela (per Odin she is stronger while on Asgard) and Mjolnir (acts as a conduit for asgardian powers), wouldn't it make sense?
I'm not saying she's weak while not on Asgard, obviously, but Hela certainly isn't at her strongest until she gets there.
Also, I assume Hela had no issue destroying Mjolnir because in her mind, the dwarves would make her another weapon to fill the same role.