i guess the 50% charge in 30 mins is a good trade off. ...
If it wasn't metal they could have the wireless + quick charging (like the S7/S7 Edge). Since it is fully metal though they cannot have the wireless. That is the trade off for the body change.
I still don't get the appeal of wireless charging. The only benefit is not plugging in a cable, but it's infinitely more confining as you have to lay/set down your device and most likely can't use it. If you are using it, you're draining the very battery you're trying to charge. Until someone comes up with over-the-air wireless charging -- thank you very much Nikola Tesla -- and not over three feet but 10-20 feet, then it will be beneficial. Until then, QC 3.0 and a USB-C cable are the de facto standards to beat.
For me it is like this .. I always put my phone on my PC desk when I get home... So I have a wireless charging pad where I always place it and therefore it just charges my phone. When I am ready to leave, get a phone call or whatever, I just pickup and walk away and it stops charging. This is convenient. Is it 110% needed? Of course not but to me that is very convenient to just have my phone charge while it sits where it will always sit.. And I can just grab and go without having a cord hanging around.