The benches are so low and the joinery so deep, there just wasn’t a need for the additional reinforcement.
So much depends on the wood and the climate that by the time you add in construction options, my head is spinning.
Project width board
Made from cedar fence boards from my local fence material supplier, it has a similar appearance to your table project.
Festool replace the bad oil and a full set of consumables including sanding disks and wiping sponges. As for the cedar, there really isn’t a whole lot of finish on it at this point so it should still age normally. I would be a shame if people choose inferior/slower/less accurate methods simply because they haven’t been exposed to the alternatives. Due to some over-aggressive joinery tuning, the long curvy rails “rattle” a little in the y axis between the two side stretchers. Additionally, she wants breadboard extensions to give a little extra seating capacity for visitors. If you’re going to have someone sitting there frequently, you might just extend the length of the table a few inches. If you can, it’s probably not a bad idea to make your center board near the width of the trough, allowing you to make a cutout right on that glue line.
If you don’t want to foot the bill for expensive outdoor friendly wood, you certainly can build this project from construction-grade lumber. What you see in the plans represents the ideal situation so don’t go out of your way to find boards of those exact widths.
You could fill it with lame content and teasers but instead you choose great projects with top-notch production value!