Table lamp is a bit disparaging, but gives an accurate idea of the function. It does contain USB parts that may need reprogramming, a battery that needs charging, etc. It would have a buck converter even if run from a brick. All that is irrelevant though, especially in the case of USB PD which is very much aimed toward charging.
It could use a power brick, yes.
I dislike them. There are a thousand varieties with different capabilities and connectors. Using the wrong one can cause damage. Most people don't know how to choose the right one.
If I can buy a generic item that can safely and cheaply be replaced by something off the shelf in any country, why would I use a brick ?