Do I really need the modular heat bed for the new Octograb flex bed?

Could I just glue or otherwise attach the magnetic base to my existing heater?

Buying both seems excessive, esp since a magnetic bed would largely negate my need for the heater to be modular.

Or is the modular heater significantly better in terms of heat spread?

Edit: I see the base of the Octograb is alum, wouldn’t that serve as a heat spreader?