It all depends on how bad your bunion is. Regardless of calling it "minimal incision" or otherwise, you will need to know what exactly will be done to your foot to eliminate your bunion and to restore the proper biomechanics to your foot. I honestly don't know much about this minimal incision method but I have read that some say the major complication could be the failure to relieve symptoms.
Sounds like you have quite a bit of symptoms and that your bunion may be of moderate to severe nature. Have you been to other doctors to get second/third/fourth opinion? You mentioned that you are desperate..what do you mean? Are you completely immobile at this point? Why won't this specific surgery be covered by your insurance? Unless you are a major keloid sufferer and worrying about severe internal scarrings (based on previous surgery experiences you had), your concern would be what will give you back good functional and asymptomatic foot and not how soon they can book you in.
You need to question the surgeon what the differences are and all the pros and cons of each method. Another thing you should do is call up your insurance (I am assuming OHIP is your insurance) why they will not cover this minimal incision bunion surgery. They will be a great source and give you more insights into their reasoning. Having a quicker appointment or having it done in 30 minutes (as claimed by some doctors) will definitely not make me want to jump into the bandwagon with both feet (no pun intended
). You should ask your doctor for a list of patients who had this minimal incision surgery done by him specifically so that you can call them up and ask for their opinions and outcomes. It is obviously hard to make comparisons as each foot/individual is different, so the outcome may vary, but this will give you a general idea of the MIS done by your surgeon.
I can only tell you to get more opinions if you haven't already as to the best procedure for you. Whatever the procedure may be, the surgeon's experience is just as important. I have read that MIS is an outstanding procedure if it is done right by the right surgeon under the ideal conditions and requirements. You could have a conventional "open" surgery but performed by an inexperienced surgeon, then your outcome may still not be ideal. So be sure you are fully informed of the procedure itself and the experience of the surgeon.
Best of luck with everything!