Review on 🔧 Enhance Arduino Mega Prototyping: KEYESTUDIO MEGA Prototype Shield V3 Board with Breadboard, Ideal for Circuit Building Projects by Brandon Rogers

When making a prototype board like this they usually use a stacking head so the pins reach to the end of the Arduino and will allow you to stack . This leaves an extra set of pins open for each connection to be soldered. In this case you have to use Dupont connectors to access the pins as they used both sets of pins. I'm sure it's fine for a one-off test project, but since I'm making a product for humans, everything needs to be soldered.