But if you only apply for one Alaska card, you end up with an "oddball" amount, way more than you need for one domestic coach round trip but signficantly less than you need for anything across oceans (even in coach). About the only thing the 40k reasonably fits is a mainland-to-Hawaii coach round trip.

That is why I don't understand the logic of applying for one "oddball" amount bonus with an airline that you don't otherwise collect miles in (and so you won't be easily able to "round up" to a reasonable redemption), if it's not an airline you can transfer out of (like Hawaiian to Hilton).