open wallets expose everyone's balance to thieves, hackers, the mafia, and a whole host of other dangerous characters besides the obligatory mention of LEA.
Not to mention business competitors. I'm a fan of transparency at gut level, but I see the other side of the question. If you were running a business, would you be comfortable with your competitors being able to trace what you bought and when? Plus, who you paid and when?
If you're running (say) a convenience store, you might not mind at all: the value-added of a convenience store is convenience. (I might well pay double for a Coke & chips if it means I don't have to spend the added time in a big-box and travel the added distance.) But if you're running a dollar store, where the competitive advantage is buying your supplies cheap, you might mind.
If you're running a start-up - or preparing to - you might mind an awful lot. If you're the head of a company lab whose value-added is patenting, you
will mind an awful lot.
So there's a glaringly definite use case for stealth addresses, particularly if open ledgers mean a push towards ultra-transparency in the business world. That's why I'm keeping an eye on the Cryptonote world for any sign that Assets or colored coins are going to be added.