[Media Boy UK]

Originally Posted by 1andrew1

I guess it's because all the matches are played in Scotland.

Nope - from link:

One Welsh side and one from Northern Ireland will be guaranteed a home tie.
Draws will be regionalised throughout the competition and seeded for the first three rounds, with the final to be played in March.

"We are very pleased to be supported by Uefa in delivering an element of cross-border competition through the invitation to our colleagues in Northern Ireland and Wales," said Scottish Professional Football League chief executive Neil Doncaster.