Apple's logo? Looks like an apple.
Exxon's logo? Says Exxon.
Google's logo? Says Google.
Shell's logo? Is a shell.
Chevron's logo? Has a chevron in it.
The first time I saw Uber's new logo, I said "wow, I have no idea what this is," which is absolutely the opposite thing you want a customer to think. You might say "oh, but it says Uber right underneath the icon on my phone." Which is accurate, but many customers wouldn't recognize the logo on the car without additional text, which COMPLETELY misses the point of having a logo in the first place.