Character building in 5e is all about making choices. Half-orc or elf. Rogue or Paladin. Multiclass or single class. ASI or feat. If it were my table, I would be saying to the players that they need to make the choice as to which is more important to them.
In my opinion, the evidence that it should be a choice between feats or ASIs should be self evident. Aside from the rules stating that this is the case, taking the feat at level 1 as a human variant takes 4 of those +1 ASI away during character creation.