Yes. It has actual objectives, progression.
You not only get to customize your cab, there is a huge number of different cabs with different characteristics and everyone has several upgradeable parts that influence gameplay. You unlock new cities, objectives... Hell, the game has a storyline and some chapters are genuinely funny.
All this in a free game with (simplified) arcade fashion gameplay. If you want to spend a whole hour in it they charge you like.. a buck or two.
I really don't have a problem with this. It's mobile gaming done right. Sega's mobile games are VERY good, and show off Sega's heritage best than say...Alien Isolation. Because Sega is all about the quick but meaningful experiences.