It is difficult to predict how alternative VPs would play in the swing states that are likely to determine the election (all the more now that it is less clear who the Democratic opponents will be). Beyond crude voter demographic preferences, some of the electorate might believe that Ivanka as Veep could usefully moderate some of her father's excesses.
But as long as the likelihood of Trump's re-election would not decline too precipitously, there is an argument that choosing his eldest child would further Trump's interests. Even if Ivanka hurt his chances, Trump might figure he has enough of a lead that he can still win with her on the ticket.
And if she were elected as vice-president, it would of course set her up to run for president in 2028, which would cheer Trump's base (just as some Obama supporters would welcome his spouse throwing her hat into the ring). They might believe that President Ivanka Trump would let her father usefully influence her policy decisions after he was constitutionally disabled from running again.
And if Trump has dynastic ambitions, it might be that he deems Ivanka, for whom he has a special affection, to be his most worthy successor. Or to paraphrase Sucession, he might consider her to be the most serious person among his offspring.
Dynastic presidential succession is suspect -- as the unsuccessful presidencies of John Quincy Adams, Benjamin Harrison, and George W. Bush have tended to demonstrate. And it will strike some voters that having a close relative as your running mate is deeply repugnant to our Constitutional tradition. Akhil Amar has pointed out that George Washington was father of our country in part because he did not have children of his own (and hence would have less temptation to instigate their succession). Then again Robert Kennedy was confirmed as attorney general and thereby placed in the presidential line of succession during his brother's term.
Ivanka, who has chosen to step away from the "dark world" of politics, might not be interested in such a position. This post is not about her or my preferences or what is best for our nation, but instead asks whether picking Ivanka might best serve Trump's interests.
In any event, it seems clear to me that Trump would have a second-mover advantage in waiting until the Democratic ticket is solidified before choosing his running mate -- as waiting might give him an opportunity to choose a vice-president that beneficially responds to his opponents.