^^ Many reasons, one of them is that with cable you are able to communicate in both directions simultaneously (Full duplex) while wireless radio either receives or transmits (Semi duplex) unless it is a MIMO router with separate radios and antennas for receive and transmit.
But MaxNet don't give you such a router for free..

Wireless has, until a few years ago, been all about convenient connection and
next to none about performance.
It has changed with recently introduced high speed wireless protocols with which you can get around the same speed as over a 100 Mbit copper connection.