> The result covers Perplexity only. We have not measured ChatGPT, Gemini, Copilot or Google’s AI Mode

Why only test Perplexity...? Isn't it the least popular among these?

I assume because promising trustworthiness by sourcing information from the web is specifically Perplexity's shtick. The fact that this study undermines the quality of random web sources hits Perplexity's value proposition the most.