From what I'm reading its an enterprise tablet.
The reason it currently requires a Blackberry to use the email app is due to the Enterprise BES server pin system. The security tied email to 1 device pin so they couldn't share the same login on 2 devices. That's why the PlayBook and all future phones require you to create a Blackberry ID. They're going to switch to an account based system and phase out the pin system so people can have multiple devices getting pushed the same corporate mail/schedules/conference calls. It's also why BBM will be able to open up to other platforms, by dropping the pin requirement.
You can still access other email through the browser. When they complete the BES server upgrades to support Blackberry ID (not an easy task given how slow corporations move with IT) they'll update to unlock the email and calendar apps for use without bridging.
As for the bridge pairing with Blackberry phones, the fact that email and calendar isn't stored on the PlayBook means the moment you disconnect the data will disappear from the PlayBook. For now this is good for security since it means people in a business can share a corporate pool of Playbooks and bridge as desired without worrying that someone else will be able to read their email or see their schedule. It also means when one is inevitably lost no sensitive data will be on it.
PlayBook can wifi tether to any smartphone of any brand that can wifi tether. Bridge is just device pairing, it doesn't share Internet. You can tether and bridge at the same time.
The reason it currently requires a Blackberry to use the email app is due to the Enterprise BES server pin system. The security tied email to 1 device pin so they couldn't share the same login on 2 devices. That's why the PlayBook and all future phones require you to create a Blackberry ID. They're going to switch to an account based system and phase out the pin system so people can have multiple devices getting pushed the same corporate mail/schedules/conference calls. It's also why BBM will be able to open up to other platforms, by dropping the pin requirement.
You can still access other email through the browser. When they complete the BES server upgrades to support Blackberry ID (not an easy task given how slow corporations move with IT) they'll update to unlock the email and calendar apps for use without bridging.
As for the bridge pairing with Blackberry phones, the fact that email and calendar isn't stored on the PlayBook means the moment you disconnect the data will disappear from the PlayBook. For now this is good for security since it means people in a business can share a corporate pool of Playbooks and bridge as desired without worrying that someone else will be able to read their email or see their schedule. It also means when one is inevitably lost no sensitive data will be on it.
PlayBook can wifi tether to any smartphone of any brand that can wifi tether. Bridge is just device pairing, it doesn't share Internet. You can tether and bridge at the same time.