Are these Addresses Invalid ones?
You're correct, they're valid addresses, just that nobody will ever have the private key that corresponds to them.
As for why people send money to them... sometimes just for fun, and sometimes to encode data on the blockchain. This particular transaction might be a dust attack, of which the goal is to uncover which addresses are owned by the same owner, in case the owner attempts to spend the dust along with other coins in their wallet together.