The work area is 10.25 x x10.25 x 2.00 so you won't be doing any large projects on it. If you get the bundle you get a DeWalt DWP611 1.25 horsepower router, our solid aluminum router mount, one 1/4″ carbide end mill, and basic clamps at a cost of $170 which is probably not a bad deal. I would add a 1/8" collet for the router instead of trying to use a sleeve adaptor but that is my personal taste.
It has Nema17 motors so don't expect it to be a speed demon power machine. This can be a learning experience or a pain in the neck. One good thing is I think the Router Forums does have a few GRBL users now so hopefully, some of them can help with the software and settings for the machine. If you can learn to work within the limits of the machine without topping the Z-axis out that will be a big plus and if you go to a larger CNC you should not have problems designing projects for the larger working limits.
You ask about the homing switches and one thing that might show you their value would be when cutting a project. You home your machine, move to the origin of your project, then record the readings, next you would zero XYZ on your project, start cutting on the 2-hour toolpath and then 1.5 hours into cutting the power goes out. Since you have the homing switches and recorded the readings at the origin of the project you and rehome then goto the readings you recorded then zero your XYZ. Now you will be back where your toolpaths start. Without the switches, you can get it close but if it is not close enough then you just wasted 1.5 hours of time and possibly the material you are cutting. You can set it up so the home position is on an index point for all your projects and not have to record any readings.
Are they worth $30, they should be ready to mount and plugin or screw in? Or, you do have the option of purchasing the switches and wire yourself and making the brackets to hold the switches on the machine, then mounting the brackets and wire it all up and figure out where to hook up the wires. Another option is to live without them.
I'll try to help but I have limited knowledge of the free design software and GRBL controller. I can output some test files for you to run to make sure everything is running in the correct direction and if not what needs to be reset.