Seems to me like art is art if the person who made it feels that it's art, and that may or may not be a component of the process that went into an apparently artistic product. Artistic products seem more likely to be "art" of there's no specific value to them, and they exist to exist or to add some abstract element of decoration to world. A former theatre friend of mine once got mad when I described art as having no intrinsic value, but that doesn't mean it has no value, and I don't think it fundamentally changes the non-art noun of what's produced; a painting/print can be just a decoration, and/or it can be art, but the fact that it's art doesn't change whether it's a painting or a decoration or the type of object. That may not be the case of course if the resulting object is an artistic illusion, such as a table that's not a functional table because it's made of cake, but again I don't think it needs to get that deep for the point to be true.

Likewise, software that was produced artistically may or may not be better, or more valuable, or distinguishable in any way from other software products, but if the author feels like it's art it may be art. That may be because there's no tangible reason for it to exist other than a creative endeavor, in which case maybe it's not actually software.