No, because each core is emulating a physical thread from the GC/Wii, the CPU/GPU. Splitting those threads in half will most likely slow down the emulator due to having cores wait for timings for each other, which would be a pain in the ass to write anyways.
The biggest difference between 32 and 64 bit, read this lovely article: https://dolphin-emu.org/blog/2014/05/19/obituary-32bit/
The biggest difference between 32 and 64 bit, read this lovely article: https://dolphin-emu.org/blog/2014/05/19/obituary-32bit/