Coaster,
You've just had two answers from two different schools of bow making: Fiberglass laminated bows of KennyM and board/self all wood bows from George T. It depends on what you want to build and how fast you want to get it finished.
The Laminated bows don't have to be heatcured but, as KennyM stated above, it is a precaution to the glue giving way on hot days, especially stored in an hot enviornment.
The all wood self/board bow staves can be cured over time without the hotbox but can, also, be speeded up with carefully applied heat.
It all depends on what you want. Hope this helps.
Oh, yes, personally, I've used the hotbox to dry wood and make venison jerky! So I like the hotbox. :D