All ports on Apple's laptops behave the same for charging - they'll continue to provide power while sleeping, but won't start providing power. If you want to use it as a battery in your backpack while it's closed you have to plug your phone in, wake the computer up, then put it back to sleep. At least that was the case last time I tested it.

For the most part they don't need colors because all of the ports are the same. One recent exception was that the 2016/2017 MBPs had inconsistent Thunderbolt bandwidth because they didn't have enough PCIe lanes. IIRC left side had full 40Gbps ports but the right side had 20Gbps. The 2018 version has full speed on all four.

EDIT - another potential point of confusion, they don't mark Thunderbolt ports vs USB-C ports. On any given device they're all the same, but they expect you to know that the 12"-mini-macbook is just USB-C while the Pro and Air are all Thunderbolt.

So yeah, it'd be helpful to have some symbols on the laptops. They do label ports on their desktops. I assume this comes down to Ive not wanting labels on his beautiful chunk of aluminum where someone might accidentally see them while using it.