That goes to my second point, though. Right now the "right to abortion" exists because of SCOTUS's (strained) interpretation of the constitution. If Roe v. Wade gets overturned then the legality of abortion depends on the states; the prez would have no say.
From an election stand point it really only matters whether they would appoint a Supreme Court justice who agrees or disagrees with the reasoning of Roe v. Wade, and I think that line is pretty clearly drawn between Republicans and Democrats.
I think the questions for Republicans are just as pointless, but it's somewhat understandable since abortion is a much bigger issue for pro-lifers than pro-choicers (stopping murder vs promoting women's right).
A president has much more influence on abortion than just appointing Supreme Court justices. They also appoint lower level judges which have a bigger influence on abortion than the SC's few opinions. Furthermore, this whole thread is about whether Planned Parenthood, that nation's biggest abortion provider, should continue to receive tax dollars. As we've seen, the president plays a role in that budget fight. Further, the president controls the administrative bureaucracy, which likewise has an influence on abortion providers.
Finally, one's views on abortion may have broader implications on character. There's a spectrum of pro-abortion supporters. On the one end are the folks who think abortion should be allowed only in certain cases or early in the pregnancy. I don't think they've thought deeply enough about the issue, but they're not crazy/evil. On the other end, you've got the "abortion for any reason, no matter when, as long as there's still a toe in the birth canal" NARAL Nazis. They're crazy/evil. Do you want a crazy/evil person in the White House? I don't.