This is great wood. To begin with, it has quite a bit of tannin, which helps protect for bugs and rot. For that reason, it is often used in ways that are exposed to rain and/or touching the ground, such as with fence posts. In Japan, its used in old traditional homes for vertical beams and base beams (which are in close proximity to the ground). I've seen base beams of abandoned houses that have been covered with wet soil for decades still retain its strength (even though the surface may be a bit mushy). And when possible, I try to get old vertical beams to use in my own projects (some being 100 years old or more, and stronger than ever)
For projects, the wood is pretty hard, and gets even harder after drying. It'd be nice for outdoor furniture too because its so good with rain. Also, it has little trouble with warping, and shrinage is less than most woods, but it does tend to get cracks along the grain if left unfinished and constantly exposed to the elements (though decay is minimal). The grain is straight and it carves well. I think you'll like working with it.
As firewood, its not ideal because of the tannin. But it does split easily. Its often used in Japan for hearths since it doesn't easily catch alight. If the fire is already going, it'll burn OK, but it burns slow and makes good coals. Traditionally its burned in floor hearths with four logs of it pointing inward and a small fire in the center. The chestnut burns slow and keeps a hot coal on the tip when the four pieces are next to each other. As they burn away, they'll be pushed inward to keep the embers burning. If properly dried, the smoke will be minimal. It gives off a distinct bitter-woodsy smell when burnt.
One method I like to do with chestnut, is once the piece is finished (like a table) instead of using varnish or stain, I take a gas torch and burn the surface of the wood till black, then scrape the loose crust off with a soft wire brush or steel wool. I'll then wash it with a sponge and water, leaving behind a deep brown/black color. Then wax it up with floor wax (the harder stuff, not the liquid kind) and the result is pretty nice, sometimes there'll be thin cracks created that give a neat texture. You can also do each part individually before assembly, but you'll need to account for a slight decrease in size when putting it together.
