Most of Lua was nicely obvious and intuitive, but ~= was always one of the weird sharp edges. I could maybe see the argument for using it if ~ was already a negation operator of some sort (like C's bitwise complement) but Lua doesn't even have that. Instead you get something needlessly non-intuitive and subject to misinterpretation by anyone who isn't a Lua native, as ~= as an ASCIIfication of ≃ is pretty common.