I agree that Crepes are amazing - I make them often (Nutella and banana mostly, sometimes just sugar), but I disagree that Flambe improves the flavor at all.. There is no need to Flambe the dish prior to serving it.

Almost all flavor is in the aroma. Flambe does nothing to add flavor - at best it is removing those precious aromatic compounds and at worst an inexperienced cook is going to burn down their kitchen. Flambe is all for show.

If you want to add flavor from alcohol (like Grand Marnier), you should just render it down into a syrup. Anyway, that's the advice I got from a better chef than myself, just passing along the knowledge.