I bought an ESP-01 adapter (initially I thought this was the WIFI module):
Than I bought the 'real' ESP-01 (which is not arrived yet):
However, according to this link: connect (sorry it's in Dutch), but the picture shows that the ESP-01 is directly connected to the 3.3V of the Arduino.
My question: why bother using the adapter card? Or does it give additional security/protection (and what)?