Thank you @abh12345 for all the support with this post! Yes, a 120 SP, 1% vote at 100% VP may end at 0 contributions to the author rewards and therefore no eligibility to curation rewards.
Voting trails are a very good example, I didn't think of them before! Following a trail at a comparably low % may indeed lead to wasted VP with no gains for neither the other nor themselves as curators.