All comes down to use and environment. For backpacking I've carried a kukri, pruning saw, machete, and hatchet, and currently carry a machete (mostly just for fun/difference and experimentation). Where I do most of my packing I have no need to clear lots of undergrowth, but do need to make the wood that's available into something that will burn - even when wet. Push comes to shove, a hatchet with good technique can do a lot more with a lot less energy if the wood you're dealing with is relatively hard. Consider, you have to work a lot harder pounding nails if you're using a light hammer. The same principle applies to a hatchet - way more energy delivered across a smaller area. Admittedly, choking up on a hatchet for smaller chores is not much fun, but it works - that's where a smaller knife comes in.
If you need one tool to clear dense brush, chop saplings/vines, do smaller camp chores, then the machete is King.
Sears didn't carry a machete.
An axe is still incredibly useful, especially if the dang chainsaw won't start.