I’ve used it for some replacement sash and exterior trim in my house, especially the eaves and fascia. I live in a designated National historic district which limits what exterior treatments are allowed to those that are like the original, so all wood sash, doors, and trim. No vinyl siding in these parts 🙂 .

. Accoya is plantation grown Radiata pine that has been treated with ascetic acid ( vinegar) to rot proof it and insect proof it. No insect wants a mouthful of vinegar. I’m not sure the process used. Probably autoclaved.
A couple sash mills around me use it almost exclusesively. And a couple fellows I know use is for almost all the exterior custom mill work they do that is to be painted. Though it costs more than untreated woods, they feel the reduced labor from its uniformity and easy supply chain is worth it.

It works like some of the softer pines like Eastern or Western white pines. As such you need to keep your tools really sharp to avoid tearout.
But it is generally pretty nice to use.

The treatment limits your choice of fasteners to metals that resist corrosion well like Stainless Steel, bronze, or naval brasses., and if you use stainless, it should probably be a marine grade like 316. I’m not sure if the more common 304 Is good enough in a wet environment due to the treatment. . The accoya website says to use “high quality stainless steel” or nonferrous metals. I took that to mean 316. You’ll have to research that. ( I actually have mostly bronze fittings in my old house)

Stay way from mild steel or aluminum.

Lastly, pay attention to keeping your tools well oiled and free from the shavings and wood dust for the same reason as fastener selection.. that would include any power tools like bandsaws or table saws with cast iron surfaces. Keep them clean and Close your tools chest.