Hi @sxlabs, welcome to the community 
The Spreadsheet File node can read (most) files using ; as a delimiter just fine, but would indeed not be able to produce such files currently.
So I’ll convert your question into a feature request, allowing you and other users to vote on having this implemented.
In the meantime, you could consider workarounds such as manually writing your CSV file using a bit of code, then converting it into a file. Here’s a quick example doing this:
This example returns a CSV structure using ; and looking like so:
id;name;email;notes;country;created
23423532;Jay Gatsby;[email protected];Keeps asking about a green light??;US;1925-04-10
23423533;José Arcadio Buendía;[email protected];Lots of people named after him. Very confusing;CO;1967-05-05
23423534;Max Sendak;[email protected];Keeps rolling his terrible eyes;US;1963-04-09
23423535;Zaphod Beeblebrox;[email protected];Felt like I was talking to more than one person;;1979-10-12
23423536;Edmund Pevensie;[email protected];Passionate sailor;UK;1950-10-16
Hope this helps!