As for potential future connectivity, if the EU (amongst other countries) mandate USB-C as the connection standard it would certainly make iPhones interesting as cameras because users would finally be able to transfer 4k or 8k footage at speed off the phone as well as potentially charge at high speeds (at the potential risk of battery health?).
Lightning already charges about as fast as Apple probably wants (up to 27 watts). There are phones that charge at 50+ watts but it's not likely Apple wants to get there. USB-C iPhones I predict will charge up to 30 watts which is where the iPads with USB-C are at, only 3 more watts.
Battery health is okay with fast charging, they just make sure to check the temperatures and ensure the charging rate isn't high when the phone is hot. And they slow down charging as the battery percent gets higher.
Is there any way to distinguish USB-C cables from one another? Which cable supports PD at what wattage? Which is a 5/10/20/40 Gbps cable?
And which ones are TB3/4?
Usually there are labels but you have to understand the labels. If they say SS and they have the USB logo, they are probably 5 Gbps USB 3.x gen 1 cables. If they say SS10, they are probably 3.x gen 2 cables (3.1 or 3.2, they are the same when gen 1 or gen 2). If they say SS20, then it's 3.2 gen 2x2.
Thunderbolt cables need the Thunderbolt logo:
https://en.wikipedia.org/wiki/Thunderbolt_(interface)#/media/File:Thunderbolt_Symbol.svg
So if you see the Thunderbolt logo you will know it's a Thunderbolt cable.
The PD rating is split between 60 watts, 100 watts, and 240 watts cables. You pretty much have to look at the manufacturer's website, packaging, or some review somewhere to see its PD rating, or you just test it out yourself. A cable might also say on it how many watts it has. 240 watts cables are brand new and just came out and not too many devices use more than 100 watts for the time being so you can discount needing 240 watts yet.
The big problem is how you can't easily get all the features in one cable, including Thunderbolt, and you sacrifice something to get all the features or you pay a lot of money. Apple's passive .8 m Thunderbolt cable has all the features (and being passive supports the new 80 Gbps mode) but it's only .8 m, Apple's 1.8 m cable costs $130 and it appears it won't support 80 Gbps because it's active and not certified for the new 80 Gbps mode, same for the 3m cable which is more expensive at $160.
