Yeah, you just do a single click on "+" (which says "Start chat"), and then it says on top "Start a conversation with someone using their name, email address or username (like @foobar:matrix.org).", so you just type in @username:server. Is it difficult? Could it get any easier? There might be other ways as well, such as the one you mentioned.

Apparently there are more ways! You can provide your phone number so people can find your Matrix ID from their pre-existing contact phone number.

Seems like it has everything a non-technical person would want.

Only marginally, it is still very easy without the QR code.