Well lets take Mt Gox as an example, it wasn’t the tech, it was their incompetence. Otherwise the hackers would have nailed everyone.

from India's top digital payments firm bets on local expertise to fend off rivals | Reuters

“It was a well-known issue that every major exchange in the bitcoin community knew about and had solutions for. Mt. Gox did not,” said Jordan Kelley, chief executive of Robocoin, the world’s first bitcoin ATM maker.

In addition, hackers aren’t going to be anywhere near as incentivized to get their hands on your files.