Is using splintered wood more efficient to keep a fire going?

Vs using a stick.

Depends on what you’re burning it in, a brazier? Not so much. But a wood stove has a long burn time compared to the brazier, or really anything else.

Use sticks or logs for light, splintered wood for batch crafting.

In a stove or fireplace you don’t waste anything, but everywhere else the stick is much more efficient.

More efficient? I guess this must be a recent change. I only noticed because I had a fire burning for about three seasons. I accidentally dumped all my logs into a stone fireplace and it just kept going. It lasted so long, I got confused when I couldn’t make new stuff one day. Turns out, many things need light, but when you have a perpetual fire burning, you forget about that.

I’ll use that until I find atomic lamp.

When resources are scarce I usually use splintered wood to start a quick temporary fire (that is, after any junk I may have).

Also, if you need a fire for cooking, or anything else, in a batch that may take a long time, you only need the fire to initiate crafting. After that, the fire could go out in the middle crafting and it will still complete. This is kind of an exploit, but it saves fuel.