Even as far back as v0.7.x, I don't remember any "Make EPUB" button. I vaguely recall that early, early versions of Sigil worked on individual files that you then had to "build" an EPUB from, but that's gotta be clear back before v0.3.x.
Also... thinking the metadata popup "looks strange" is an opinion you're allowed to have. But "can't use it" is not exactly very accurate (or fair) You may not know how to use it ... you may not enjoy using it, but "can't" doesn't really enter into it. Click on stuff. Use the Add Metadata button to add new metadata. Highlight some metadata and use the "Remove" button to remove it. Highlight some Metadata and use "Add Property" to add additional properties to existing metadata. Double-click on the text boxes to enter/change text. That's "using" the Metadata Editor.
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