I wash and press all my fabric as soon as it comes in the house. A larger ironing surface would really help with that. I do press each seam in the block as it is being sewn, but each seam of the top must also be pressed as the top is assembled. A larger ironing surface would help support the top while those long, long seams are being pressed. During quilting I have found that those long seams are the ones that need pressing the most, since the shorter seams in the blocks are generally held down by stitching.
The batting and backing have to be cut off the quilt after quilting and before binding. A large cutting surface is necessary for that, and the wider the better to help support the quilt.
I do find that I use my large cutting surface (with multiple mats) far too much as just another horizontal storage. (In other words, stuff gets put on it that doesn't belong there.) As a result I frequently have to clear it off so I can use the whole thing for its intended purpose. Occasionally I need to cut pieces of fabric that are pretty large. Backing fabric, background for applique, corner and side triangles for on point designs - these are just a few. I also use my cutting table for assembling applique, for tracing with a light box, for laying out fabrics for consideration in a quilt.
So yes, bigger really is better.