This is not a waste of money. We should be spending billions, not millions, on the design/development/deployment of a technology to protect against asteroid hits.
If an asteroid comes our way, the billions we spent will be chump change compared to the trillions or quadrillions in damage we would avoid. If no asteroid comes our way we would have developed some interesting technology which might come in handy for a moon mission, mars mission, space mining, etc.
Asteroids are the mothers of invention.
Tunguska size impacts are believed to happen at least every couple hundred years. Not a big deal in unpopulated early 1900s Siberia but a midwest impact today would be really bad.
Iran’s nuke ambitions are most likely more of a danger.
If an Eros-sized asteroid hits Earth there will be no human race to tax for damage repair. It would be pretty much a game-ender. Nearly all life on the planet would be annihilated. The Chicxulub asteroid thought to have killed off the dinosaurs was only about 8 miles in diameter. Eros is much bigger. It's only a matter of time and celestial mechanics until such an disaster occurs, and I agree preparations are needed.