Considering balconies are outdoor areas they are exposed to the wet weather conditions. Like all wet areas that are tiled, balconies must be waterproofed prior to tiling in order to protect the concrete and prevent any water leakage.
Is your Balcony looking tired and worn, with cracked and deteriorated Grout? Then you are probably due to re-grout your balcony. Re-Grouting a Balcony is beneficial as a preventative measure to repair your balcony BEFORE it starts to leak.
Visually there is not much difference between the two products. They are both used to seal the joints between your tiles. The difference is more in the chemical make-up of the products and the benefits that come from a more waterproof and flexible product.