A 2" mini-louver vent will only provide 1.5 square inches of NFVA per hole.
See this chart at this link:
You would have to have them run continuously and you still would only equal the same venting as either a continuous strip soffit vent or the Smart Vent by DCI Products Inc., but I am positive that this was not the proposed method of installation and even if it were, what would the structural stability of the soffit wood be like with so many holes cut right next to each other?
Most roofers do not climb a ladder to do the majority of their estimates, so it would be likely that the under shingle profile of the Smart Vent may have escaped their attention.
But, I find that only a really quality conscientious contractor thinks so far out of the box to improve the soffit ventilation correctly and it does add considerably to the quoted price for all of the additional materials and labor, that many would prefer to just not address the correct solution and be on their merry way offering a cheaper price, but not the correct solution.
Also, I only found out about the product around 2001, myself, but I have been using it on about 50% of all of my roofing project in recent years, where called for.