For the big conferences at the Boardwalk-area conferences, they tend to need 1000+ hotel rooms held. It's usually almost all of YC, a big chunk of BWI, some of BC, and then they hold some units elsewhere as well. You want to see bananas, look at the Gartner hotel list:
https://www.gartner.com/en/conferences/na/symposium-us/venue-travel. IT Xpo has nearly 6000 attendees, PLUS all the exhibitors and they use upwards of 10k hotel rooms.
Smaller conferences, like the CME stuff, tend to have a smaller hold and consolidate entirely to YC or BWI.
A conference slams for revenue. Every bit of electrical power setup, every social event, every last packet of Cheez-Its served is revenue for the Mouse. And then there are the specialty events, like the breakfast that can ONLY be booked by conventions featuring Elsa, Sven and Kristoff, or the cocktail events.
There;s not value in converting the convention centers at CSR and Boardwalk to hotel units. Convention business provides some great diversification of revenue, catering, Disney Institute revenue, etc.
Now, if we want to talk about "tearing down the neglected and sad Contempoary convention space and building a DVC," that's a lot more likely. Disney has poured a lot of cash into both the Boardwalk area space and the CSR convention space, while letting the Contemporary space peel paint and smell weird.