Good questions.

Image-only PDFs (scans): These are the hardest case. If a PDF is basically high-res images (like iPhone scans), browser-based tools have limits compared to ImageMagick, which has much finer control over resampling and JPEG compression. Ghostscript-style pipelines help, but ImageMagick often wins if you’re willing to discard more detail. Improving this is on the roadmap, but it’s genuinely tough in-browser.

PDF forms: Adobe doesn’t own forms, but editable PDF forms are extremely complex and poorly standardized. Many free tools avoid true form editing because it’s easy to break files. That’s why I haven’t enabled it yet—possible, just time-consuming and error-prone.