head bolt heater?

Is that like an Engine Block Heater?
The "do I really need one" question begs a definition of the word "need".
Will the car start and run without one...sure.
Will it reach peak operating efficiency and thus obtain maximum Fuel economy and minimize emissions without one...definately not.
Will it warm the cabin as quickly without one...definately not.

I use one down here in the more temperate Ozarks of SW MO with a garaged car. I don't "Need" it, but can say that my winter FE is noticably better, particularly on shorter trips (ie. 4-5 miles to take kids to daycare) than without it. I get heat in the cabin more quickly, and it's nice to have that.

The decision is purely yours, but if you do experience cold winters and need to park outside then it will make a marked difference in your winter driving and FE experience.