TV Debates - Irish party nonsense

A load of nonsense is being talked about including Northern Ireland parties taking part in TV debates. There is a fundamental difference between Plaid Cymru, SNP and the Irish parties. Plaid and the SNP have to run against the main UK parties - Cons, Labour and Lib Dem, the Northern Irish parties do not. They run against each other. What on earth would be the point of Sinn Fein or DUP debating against parties who are NOT their opponents? Plain silly talk.