I'm on my 2nd version of my own CNC and looking at the video, I think you will learn a lot but you will be ultimately disappointed with the accuracy & repeatability and without close loop servo controllers, you're going to find that it will tear itself apart if you're not there to stop it.
I learned the hard way. Spent $$ buying a basic kit from pdjinc.com - without the controller & built my own. It's based on 80/20 frame with linear guide rails. Found that because it was put together with bolts and screws, it was constantly getting out of alignment as even a small bit of movement compounded over the 4'x4' area was enough to make things not accurate. The X Axis would get out of step & skew the gantry when something got hung up (ball screws can get gunk in them and they lock up) and if it wasn't for me being there, it would have torn itself apart.
Looking at the woodsmith one, with it made of wood, I just don't see how you're going to have the accuracy to do anything worthwhile.
I do so much with my CNC, such as dado's, dovetail slides, bowties to strengthen cracks in slabs, mortise & tennon, etc that I was going crazy with a few thousandths of an inch out (bowtie won't fit), or dado's that aren't the same width 24" apart - so your casework is tight on oneside & loose on another.
So, I enlisted a friend of mine to use his Haas mill to make all new brackets with threaded inserts and I upgraded from the 1/2" ball screws to 1" ball screws and added servos to ensure it won't get out of whack and lengthened the bed to 6' instead of 4', so now it's a 4Ă—6.
I was into this for about $6K initially, and then another $3-4K for the complete overhaul.
I can see the appeal of building your own. I learned an incredible amount, but the accuracy on a wood built CNC is going to only be able to those 3D relief carvings because they don't need the accuracy & no one would be able to tell the difference. If you want to do anything that requires repeatability and accuracy (dado's, butterflies, mortise & tenon, etc) you're going to need to have a more stable & robust platform.
I can't tell you how much I've enjoyed my CNC. It allows me to do things like the past 3 days where I cranked out 20 charcuterie boards with the same handle on all of them. I use vacuum hold downs to make setup a lot easier (most of the 3 days was jointing, glueing & planing).
But I would really tell you to head over to cnczone & check out their builds. They are serious. It's going to cost, but in the end you'll have a robust & accurate CNC.