It looks more like a cover page to me -- the characters are more posing than acting, and the composition leaves plenty of room up top for the title and publisher logo. The smoke on the bottom might be to give room for the creator credits on the cover.
I went back to the listing I won and it is definitely described there as "cover art":
"Star Trek Deep Space Nine Original Cover Art by Rod Whigham ~ Dr Bashir Andorian"
But when I received it, I was struck by the positioning of all that smoke. Mind you, some intended covers do become splash pages at times, and others are relegated to a "pin-up" section when they don't pass muster as a cover.
Who knows how many unpublished lost comics are out there! My fellow Aussies, Glenn Lumsden & David DeVries, were commissioned to do a Klingon-heavy TNG storyline for DC when now-late Kim Yale was editor. I helped them out with an episode guide I'd compiled - it was after their TOS one-shot, #34 Aug 1992 - and they named a Klingon after me, I understand. The whole script was finished, approved and ready for the art, but got lost in the shuffle during the departure of Ms Yale, and then they got busy with a "Phantom" mini-series.