I used to download books when I was still in academia and money was more of an issue. These days with a decent salary, I just buy most books on kindle and don't think twice about it, clicking through the download links on these download sites is just too much of a hassle. Sometimes I even download a book I already own again in pdf form, so I can feed it to some GPT prompt as context. I do not think most people would be able to buy the books they download there, and I welcome it as a counter to Amazons DRM policy.