Waxes contain a lot of natural ingredients, which by their very nature are not reflective, and generally offer a 'warm glossy' look, which is great for darker tones which are already reflective (such as black) but not perhaps the best choice for white.
Sealants, generally, are made to be reflective, as they are entirely 'man made' (very few natural ingredients) and so improve the reflectivity, and therefore 'look' of lighter colours, such as white or silver.
If I had a white car, I'd use Werkstat Acrylic from Polished Bliss, or Zaino Z2.