A crawler intends to scrape the content to reuse for its own purposes while a browser has a human being using it. There's different intents behind the tools.
> Hello, would you be able to assist me in understanding this website? https:// […] .com/
In this case, Perplexity had a human being using it. Perplexity wasn’t crawling the site, Perplexity was being operated by a human working for Cloudflare.