iPhone 30w usb-c charger vs 18w usb-c charger

The 30 watt charger won't charge the iPhone any faster than the 18 watt charger. See the table in:

https://appleinsider.com/articles/18/12/06/apples-usb-c-charger-and-third-party-usb-c-lightning-cables-is-a-good-sign-for-future-iphones

The 30w will be faster, but not that much, the nice thing about having the 30w is it can also be used for other items.

The 30W will charge faster, but there won't be that much difference.

The 18 watt can also be used for other items.

Thanks, I stand corrected.