Trust is useful for companies and organizations. Trust in individuals is much more shaky. Anyone can suddenly "spend" their trust in a massive scam, or go bonkers. That's true for companies too. Just look at MtGox. Still, a company like PayPal has enough trust, and if they would accept bitcoin transactions then that would be a major boost for cryptocurrencies.
Indeed. I think it would be exciting great if paypal accepted bitcoin, and i had heard that they were looking at implementing it in one of their subsidiaries on a trial basis.