Your spotted one run on a race to two (the minimum for a multirun inning). This is a pretty tough choice... Or, you can have a man on 1B with 0 runs yet produced, with the ability to be picked off, caught stealing, doubled up, or thrown out going for the extra base. Not to mention pretty much any sequence of events that happens with the hitters hitting 2nd, 3rd, 4th, 5th, 6th, 7th, etc in that inning that produce two runs in out of a leadoff walk would assuredly produced a second run had the leadoff homer took place instead.