Since I have to dot all the eyes and cross all the tees: Legitimate use is anything that is not a spam attack, meaning where people use bitcoin to transfer money or in other words when Bitcoin is the "peer to peer digital cash system" that it was intended to.
If the sole purpose of bitcoin was just to transfer money what's the role of OP_Pushdata ? And especially OP_Pushdata4 ?
Seems that the creator had a different view than you .