It's mostly about the tablesaw...huh?
The table saw is finicky about the condition of the wood it will safely accept...... huh?
Any wood that is NOT flat on the bottom and square on the edge that you place against the fence MAY be cause for a kickback. This is because the wood may twist as it's going past the blade, bind up and get kicked backwards OR it may lose contact with the fence and ride Up and OVER the blade back at you. The use of the jointer prior to the tablesaw will prevent this. Using the planer first will not..... huh?
Because the planer is a "two sided" machine, it makes the wood a uniform thickness along it's length and will duplicate any slight curvature in the board. The cutter is on the top face of the board, so it will duplicate what ever is on the bottom face. It is also "power fed" unlike the jointer where the operator controls the feed rate and pressure down on the tables.
The jointer is a "one sided" machine and only performs the cutting/ material removal on the bottom face, leaving the top face alone. The jointer has two tables, an infeed and an outfeed which are separated by the cutter. As the wood is fed into the cutter the depth of cut is determined by the amount of offset between the two tables. The greater the offset, the greater the depth of cut. After the wood is both flat and square, it's safe to run on the table saw, AND both edges will be straight and parallel!
I use mostly rough saw wood that was milled from trees on my property years ago. I will also buy rough sawn wood at the mill in special species for special projects like Zebra wood, Teak, Walnut and some Maples. I can select the type of grain orientation this way, quatersawn for straight knot free applications, OR plainsawn for most of the others. Where the wood has been sawn from the initial log determines how it will react during the drying process. If the grain on the end is vertical it's less likely to cup. If the grain is arched, it will cup toward the smaller side of the arches. The more you learn about how wood moves, the better your projects will be!