Local conversion vs cloud conversion.
Cloud conversion is not automatically bad, and local processing is not automatically possible. The important thing is transparency: users should know where the work happens before their file is processed.
When local processing is better
Local processing is ideal for everyday image work: WebP to PNG, JPG or PNG to WebP, compression, resizing and EXIF removal. These jobs can often be handled by browser APIs without uploading the selected file to a remote server.
Local tools are especially useful for personal images, unpublished drafts, screenshots, client previews and anything that simply does not need to become a server-side job.
When cloud conversion is useful
Cloud conversion becomes useful for tasks that are too heavy or too specialized for the browser, such as long videos, OCR, advanced PDF conversion, large archives or formats that require server-side libraries.
The key is not to hide that tradeoff. If a feature requires upload, the interface should say so, explain why and make the workflow feel different from a local tool.
The PrivateConverts position
PrivateConverts starts local and stays honest. Local tools should be simple, fast and accessible. Future cloud tools can exist, but they should be optional, useful and clearly marked before upload.