Just to address the above statement only: if you can live with Ledger's closed-source code, it's still a good wallet that doesn't require buyers of it to have their private keys split up into shards and placed into other people's hands.

The first thing that popped into my head was that this "service" would make it incredibly easy for governments/law enforcement agencies to seize assets from anyone who uses it, as I'm sure none of the three parties in control of the shards would defy court orders--and who knows, they might even give up the info without such an order.  That's the problem; you don't know what's going to happen when you're not in control of your private keys.

Ugh.  This is fucking awful.