Sure but it's also not a pink elephant and not a flower pot. It's none of those things. We have just as much evidence of those objects flying through space as we have of alien spaceships so far. So it's odd asking "So is it a spaceship or not?" just like it's odd asking "so is it a flower pot?".
Is Musk's red car a spaceship btw? Because if we are able to send such stuff to space, other intelligent beings would most probably do the same. Or they are more intelligent?
That's my point! Anything could be in space, elephants, flower pots, EVs. But they picked a particular thing out of the possible universe of objects so was curious why they picked that. It's an asteroid emitting Ni atoms based on the paper. Do we have any evidence of alien spaceships doing that that?