Well, I upgrade BiaB/RB whenever the new features and real tracks make it worthwhile to me.
That said, I would love to see 64-bit along with 32-bit, even if 32-bit is released first.
Because some people will need 32-bit for various reasons.
AFAIK 64-bit programs on 64-bit systems are faster and generally more stable.

I've been somewhat discouraged with BiaB when trying to run 32-bit Romplers as BiaB usually locks up when I try.
Sample Tank 2.5 works OK, but my good libraries are mostly in Kontakt or PLAY format.

Because of all that, I generally use BiaB as a midi generator, and RB as an audio generator.
All of this is imported into my DAW where I can use multiple 64-bit plugins without crashing.

Boyd
Win10 - 16GB-RAM - BiaB 2019 - Mixbus 4 - Slate Bundle - Komplete 10 - Ozone 8 - Neutron 2 - Waves Gold
Ample Sound Guitars & Basses - Pianoteq 6 - SSD5 - SD3 - JamStix 4 - Omnisphere - UVI Falcon - EastWest Play
Sonarworks Reference 4 -