I don't think the difference is as great as it is for torpedoes. Shields typically have less damage points than hull, and yet only torpedoes really cut through hull rapidly. (Then again, Shields regenerate while Hull does not, so those damage points, once regenerated, must be dealt by beams or cannons too)

I honestly had never heard that cannons do more damage to hull than beams. I suspect it's not that significant. It may be useful for an Escort using CRF to take out a ship's hull, but I would still use torpedoes anyway.