The only reason I could think of exporting the Audio files as 24 bit would be if you were planning on recording something in your DAW at 24 bit, and there MIGHT be a compatibility issue in rendering to the final wave file.
For most home studio setups, I really can't think of a reason to use 24 bit, unless you have a totally professional studio AND you're going to have an unbelievable dynamic range in your music.
Most home setups can get away with 16-bit recording.

Finally, I suspect there is a practical consideration. I just downloaded the UltraPak+ version of BIAB 2018. It took me like three days and was about 170 gigabytes of data. This WASN'T the Audiophile version, the standard version uses compressed files. The Audiophile version does not. If you went to 24 bit, the actual file sizes would be astronomical. Imagine a one terabyte drive to hold all of your files, and then trying to install them on your computer.

I'm blessed watching God do what He does best. I've had a few rough years, and I'm still not back to where I want to be, but I'm on the way and things are looking far better now than what they were!