Something that requires low latency, blazing fast responsiveness. If you can overcome this with prefetching and buffering, then it’s not an issue (I guess).
I’d be thinking of business websites where their page load times play a big factor in their organic search rankings. When you’re competing with sub 1 second page loads having many, many resource calls, I’d have a hard time believing SAFE could compete with clearnet.
SAFE will have many applications, but, IMHO, this won’t be one where SAFE stands a chance. Heck, most SANs can’t compete with SSD servers, and they’re not doing anything other than TLS on the stream.