Let me add to my post
How do you collect moisture,, cover it with something, plastic,laminate,etc. it's great to have it in the kitchen because you can and will spill things on the top and it gives you time to wipe it up but it the shop you should not put you pop,coffee,hot pots.etc. or anything else on the router table..
The MDF is always open,,like around the router mounting plate for just one spot..that's why the Johnson wax works so great, you can put it around all the edges and keeps the moisture out so to speak..
Look under your kitchen cabinets and you will see the spots from things that have spilled over and have run down under..it just happens.
If you put laminate on the bottom side you just made a pocket for the moisture/water to collect..( plastic bag thing ) the air will dry out the moisture if it can get to it..
Aging back to the kitchen thing,look under your cabinets in the kitchen you will not see the bottom side that have been laminate..they know it takes air to dry it out..
Same thing for the edging,you will have a small crack and it time it will fill up with junk..the Oak or what every will not act like MDF, it will move or shrink , to me it's just something you add to cover up something or to match the base wood stock..
It just takes a bump with some stock and the edging has a crack in it,that will fill up with router dust in time..once the glue drys up it's free to move..and in time it will..look at a book case that has edging on it..and that's made out of plywood.. the plywood is very stable but the wood edging is not..that's why many use plastic edging to match the plywood/MDF/PB/etc., it's very stable also..
not the glue on type but the push in slot type..