Is this a real party or some 2 percent fringe group that will form the rump end of a watered-down coalition?
That's the $64,000 Question!
In the 2015 election the party got 17.7% of the votes [...] In 2015 they joined the government coalition formed by Prime Minister Sipilä. Following a 2017 split, over half of the party's MPs left the parliamentary group and were subsequently expelled from their party membership.
-Wikipedia
So, to answer your question: Sounds like they do not represent very much of the electorate and are not likely to succeed in getting Finnland out of the E.U.
Regards,
A real party. She is a member of Parliment.