Web content can be hosted via B2. However, a domain name cannot be directly mapped to a B2 bucket. This is a feature that we plan on offering in the future, but do not yet have an ETA for.
Cloudflare can be used as a potential workaround. Details for creating a vanity url can be found here: https://help.backblaze.com/hc/en-us/articles/217666928-Creating-a-Vanity-URL-with-B2