This is their comment about how it compares to Signal:

End-to-end encrypted (E2EE) messaging apps like Signal and WhatsApp provide strong confidentiality of the message content. However, they do not hide communication patterns, such as who is communicating with whom and when. In addition, users cannot plausibly deny the existence of conversations if they are forced to unlock their smartphone. CoverDrop provides both strong metadata privacy, hiding who is communicating with whom and when, and plausible deniability, even where an adversary has physical access to the device and asks the user to unlock it.

I thought when Signal added sealed sender it was to make it hard to analyze traffic patterns on the server side. Signal would make it harder to deny communicating with someone if your phone is unlocked as even conversations with disappearing messages don't disappear themselves as I recall.

I am all for more secure communication, but in my mind, anything in this space needs to demonstrate how it's fundamentally better than signal. For the general use case that's typically pretty hard.