It’s also worth remembering that by using the module you will have done away with the governor system.
There is a way around that but whether its worth the faff is another matter. It basically involves leaving the points in place, disconnecting the condenser and mounting the module of choice out side the magneto. The points are re-purposed to act as a governor controlled cut out.
Whether “snake oil or sliced bread depends on the situation. The two currently available aftermarket trigger modules, Mova and Meco are not total “snake oil” as they do work well on many engines. Equally they aren’t all “sliced bread” as they wont perform on some engines. I have fitted many Mecos to Villiers F12s and 15s with absolute reliability and I know people who swear by the Nova for old cast iron single pot Kohlers.
Interestingly, while the Nova and Meco modules are sold as one size fits all, back in the 80s the Australian made Atom modules came in different colours and characteristics. The ones most commonly seen in the UK was the brown type 9 for chainsaws, brush cutters and other high revving two strokes. The blue type 7 was as near a general purpose as they got and the green type 5 was recommended for post 1960 Briggs with two leg armatures. Being Australian they did a special for the uncommon in the UK twin cylinder Victa.