It'll help. Ask for some customer references, maybe someone with a similar house. But it could also cause other problems. Older houses are naturally leaky and that helps keep them manage mold/mildew and radon. Your water heater and furnace could also backdraft. So that's something to consider. Modern houses are basically sealed inside a plastic bag so you need active mechanical ventilation to keep things in order.

If you have a really old house make sure you don't have vermiculite insulation which might make things way more expensive cause it likely has asbestos in it. Apart from that you can also DIY it but it's messy. Your state may offer incentives for doing it too.

https://www.energystar.gov/campaign/seal_insulate/attic_air_...

I'm not an expert but based on my personal research adding a ridge vent to the roof and getting a convection current drawing fresh air from the soffits through the attic and out the ridge supposedly makes a big difference. When you've got it all sealed up you've got a solar oven.

You'll still want insulation on the floor of the attic space, and seal off the living space from the attic.

From what I gather the main complication is keeping critters out while opening your attic to a substantial flow of fresh air. A pile of rockwool insulation sounds like a hell of a home for many small mammals, and bees can get past all but the finest of screen meshes. It seems feasible to diligently install screens on all the vents but it'll be a maintenance burden to keep them intact as the years go by.