Sometimes you go for what most of your customers already know or want, or you go for whats easier and handier, or you go for what is a known quantity and wont have legal or other problems down the line, you go for what's less volatile, etc etc.

The only reason a big company like PayPal would ever use something like Bitcoin as it is today, is not to "take advantage of what it offers", but as a "early adopter marketing ploy", to get some tons of free press and publicity (while still relegating it safely to 1/10000 of their actual businesses).