As a BitLocker user and also an Acronis user for backups I can unequivocally say there are no issues there. I can backup and restore a file without turning off or on BitLocker.

Also be aware (reminded) BitLocker is a drive encryption feature to prevent unauthorized access to the drive. Example: I steal your PC with a drive encrypted and I want the info. I could simply take the drive out of a your PC and slave it into another.... NOPE!!! If you don't have the decryption key, you'll end up wiping the drive before getting into it.

Yes, someone on the net is going to post it's not effective. Looks on your door aren't really effective, so...

Anyway I use BitLocker as another safety layer in protecting my data... in this instance in case of theft of PC.