There are technical limitations that prevent us from enabling embroidery font uploads. We don't have plans for it due to that reason but perhaps we can revisit this long term when changes to software dependencies ease the current limitations.
We upload client logo's that contain the clients font that we digitize but not the actual fonts. We transpose the designs into EMB format then upload the logo. The EMB font does not contain the font information only the expanded stitch data so the render properly and are available for download if we need them again.
Unless you want your online clients to have access to all your embroidery fonts, this might be the a solution.