The IFPA is a sanctioning body, not a marketing arm for your league. It's similar to how bowling leagues have sanctioning by either the World Bowling Congress or the US Bowling Congress, etc. They are there to make sure your competitive format is consistent with how others do it, so when you say "I bowled a 300!" it has meaning and definition agreed upon by others.
The IFPA provides approved tournament formats and rules/ruling guidelines to make the competitive experience more consistent. They also provide WPPRs, which is one way of measuring performance against other people you don't necessarily have a chance to directly play. I find these to be great tools, and great fun; moving up the IFPA rankings is important to me and I've made it a hobby the last 18 months to play more and improve.