Time is money. After a couple of years I think I've finally recouped my
investment on the jointer. It definitely speeds things up.

In my experience, rough lumber with one side cut straight is never
truly square to the face of the board. It may appear so when you are
selecting the boards, but when you let it rest in your workshop you'll
probably get a bit of movement. A jointer will make quick work out of
re-straightening and re-squaring the boards. And if you need to cut
larger stock to smaller width with a bandsaw, you are going to release
some pressure in the stock which will surely make it move (depending on
the species you're working with).

I use the jointer to generate a flat (albeit with circular cutter
waves) edge, then remove any cup on the face while at the same time
creating a square edge. Unfortunately you need to always calibrate your
jointer to make sure it is square to the fence.

If I'm joining boards into a panel, I find that the jointer really
isn't enough. It looks good, but there may be 0.01" or so gaps along
the edge of the boards. However, these edges are square.

I then take the 2 boards to be joined together and clamp them (facing
edges up) to the table. I use a long benchplane to smooth both edges
together. This removes circular marks from the jointer blade and makes
sure that the 2 edges match perfectly.

And forgive me, Norm, but if you do it this way you don't need to use
biscuits or an $800 Lamello biscuit jointer.