my 2 cents - Claude is not going after EVERY single SaaS (or maybe not yet), but after those products that are adopted by individuals that are keen at experimenting new tools (software engineers, designers etc etc).
At the same time I have the feeling Claude Design is more useful to get UI context closer to Code Claude then anything (and eventually some quick prototyping), but I might be wrong.
Either way, I've been trying to upload a 95MB .fig file and I get a generic error message without any information on the issue itself (is the file too big? not the right format? Tell me!)