The message in the description isn't very descriptive of how this mod is useful...
Vanilla furnaces are powerful — but static. With Selective Furnaces, you can control your smelting more dynamically.
Smelting with regular furnaces are already the most dynamic they can be - changing the input changes the output without needing any circuit logic. The only reason I can think of using this is if I wanted to read the contents of a furnace, which I don't think many people want to...
