Need to secure your databases from detach/attach & backup/restore methods? I haven't heard of this requirement yet, however it may make sense for certain regulations.
Of course, transparent data encryption really means that you can still see the data if you're connected to SQL. TDE just seems to add to the complexity of a backup/restore process.
Does it sound too good to be true: transparent data encryption? Well, it kind of is and kind of isn't. Let me explain. Transparent means that the application developer doesn't do anything (and if you have a third party app in which you can't do anything anyway, then this is even more important). Once enabled, the data is seemlessly protected.
But, protected from what? That's the part that needs a bit of explaining...