[OnePlus 3 Questions & Answers] yurtesen:
So many "opinions" but mostly incorrect. The answer to the OPs question is that you don't have to worry about quick charge destroying your battery. It will not have significant impact on your battery capacity. I would have been more worried about breaking the usb type-c port(see point 2 below). All things considered, after 2-3 years you will probably buy a new phone anyway and also you can always buy a replacement battery cheap. But you can simply use a normal charger which delivers <3A with 5V so you don't have to worry about anything.

1- Slow charge does not damage lithium-ion chemistry batteries. You can read about lithium-ion charging here. But neither fast charge will damage lithium-ion as long as the battery temperature is not extremely high. Also temperature at different charge stages effect the capacity decrease (source) But you will be fine as long as the battery temperature is less than 45C. The charging IC should stop the charging process if it exceeds it anyway.

2- Qualcomm's quick charge is much better than voop/dash charge from an engineering standpoint. This is why also USB organization's power delivery (PD) standard uses similar scheme. The problem is the cable and the connector. The maximum allowed current at 5V is 3A with usb type-c connector (source). If you provide more current, you need to use a thicker cable(dash/vooc cables). But you can't change the connector, and it may damage your connector in the long run to use 3+A currents to charge. Because there is a contact resistance (R) and the power lost in the connector is square of current (I) times R. Meaning R*I^2, it will wear off the connector faster. This is why some companies with some engineering skills opt in to use higher voltages instead of higher currents.

3- You can't push more current to lithium-ion battery than it accepts. The maximum current is voltage delta (between charging voltage and battery voltage) divided by internal resistance. This is why you can charge empty battery much faster. If you use an app like Ampere from play store, you can see the voltage of your battery before and after you plug in your charger. If you plug in a normal charger, you will see that it goes up a little bit. If you plug a quick charger it goes up to ~4.35V

4- Yes, there is conversion inefficiencies for quick charge inside the phone, and it will warm up the "phone" and battery only indirectly. The conversion IC are normally >90% efficient (source). This does not mean that your battery will be destroyed. It is perfectly fine to charge lithium-batteries with up to 45C temperatures (source).

4- If overnight charging killed your battery, your battery was faulty (or you had 3rd party battery?). The battery should be capable of holding 4.35v charge. You would need to store battery at 4.35V full charge for over 3 months to loose 20% capacity (http://batteryuniversity.com/learn/article/how_to_store_batteries). Having full charge few hours overnight won't destroy it unless your battery or device is faulty.

With all this information, I would rather opt in for USB-PD/Qualcomm Quick Charge solutions than VOOC/DASH solutions. I think eventually only USB-PD will remain and everybody will use it as a standard only.