There are no by-products with this

There are no by-products with this reaction. Molded pieces
made with silicone using this addition-cure mechanism are
very accurate (no shrinkage). However, handling these two part
products (i.e., polymer and Pt catalyst in one component,
SiH oligomer in the other) requires some precautions. The Pt in
the complex is easily bonded to electron-donating substances
such as amine or organosulfur compounds to form stable complexes
with these “poisons,” rendering the catalyst inactive and
inhibiting the cure.
The preferred cure system can vary by application. For
example, silicone-to-silicone medical adhesives use acetoxy
cure (condensation cross-linking), and platinum cure (crosslinking
by addition) is used for precise silicone parts with no
by-products.