Not only did Hot Wheels look great but they could do something Matchbox couldn't: race down the track. Kids like me wanted their Hot Wheels to be the fastest and it was easy to set up match races in one's room. Best of all: no batteries required; only required gravity to make it work. The iconic loop was introduced in the earliest of sets.
Battery powered devices were introduced to compete with then popular slot car tracks. These enabled Hot Wheels to zoom around a closed circuit race track.
Later ads switched to photos which were not as cool looking. But the idea of challenging to a race was very tempting. Mattel also ran TV commercials but that is a topic for a future post.