A Bavarian Weizenbier is traditionally decocted. The flavor benefits from ferulic acid formation at the 95-113F temp range, which promotes the banana/clove characteristic in the yeast profile (and it also helps lower pH for the mash as well as providing a tartness in the finish). A 122F-131F step helps break proteins down to shorter chains for better head formation and retention. A beta rest (140s) helps develop fermentables and a 154F rest will provide dextrins and mouth feel. All boil steps in a decoction bring forth melanoidan development which gives a maltier flavor profile and helps balance the aforementioned yeast characteristics without becoming overbearing.
By comparison, American Wheats are quite tame in their flavor profile. A step mash may help with head formation, but most American Wheats are fermented using either a Kolsch yeast or another clean/neutral yeast (often Cal Ale), which makes the style approachable by the "BMC" crowd as a crossover beer. Basically, the idea is to keep the IBUs low, the yeast clean and neutral, and the malt sweet and bready, and therefore non-offensive.