If you generate midsurface feature in DesignModeler or SpaceClaim, when that surface shows up in Mechanical for meshing, the thickness parameter has already been filled out for you. This is very useful if you have different thickness faces.

If you generate midsurface feature in SolidWorks, you will have to define the thickness parameter in Mechanical, but you can select all and assign the thickness in one go if they all have the same thickness.

SolidWorks might create all the surfaces at once in one go. SolidWorks might trim all the surfaces to intersect properly. You have to see what works best. My NX CAD system does a great job of automatically finding all the Face Pairs and trimming them to common intersection lines.