Sometimes folks seem to get offended in this debate. But as far as I know there is no recognized hobby definition of a variation, and so from my standpoint everyone is entitled to their own view. I personally view variations as cards changed intentionally in the printing process. I stretch that to include DP variants like the 52 Mantle, since while the differences were not specifically intended, it was intended the card would be a DP and that resulted in the difference. Same for all the CL differences in all of the 60s and 70s sets, and for the 13 DP card cropping differences in the 1963 set discussed by George Vrechek in his SCD article
I use the term variant for cards that are different from their counterparts due to some recurring unintended print defect.
I collect both, and some cards that I think of as variants get hobby recognition as a variation, such a s the 58 Herrer and 57 Bakep and 61 Fairly. Obviously if the card gets recognized by PSA or Beckett or SCD as a variation, master set or player collectors will have to have it and the value will soar
Some folks have told me they think the Campos black star is a variation. I tend to view it as a variant, since there are some partial black stars. But what matters more is how the hobby views it
I like front more than back variations, and so agree with you that the House is more interesting than the black star. But if it ever gets recognized, I think the Campos missing front border, a print defect from my standpoint, will be harder to get and more valuable than the "normal" yellow House. If the gray back House gets recognized, that may be rarer still.
As to whether the House is a variation or print defect, I have heard it argued both ways but people who know more than me about the print process have told me they think it qualifies as a variation. Whatever it is, if PSA, Beckett or SCD recognizes it, that is that
I am mystified by the recognition process, is it a science or a whim...I lean to the latter
I have come to really believe that if you take any Topps card from the 50s, 60s, 70s, 80s and early 90s ( as far as I have looked so far), and you look long enough and hard enough, you will find some variant ( difference) resulting from some fault or defect during the printing process