For a simple service, it adds a bunch of time to waste.
My 2011 shield is 5 pieces. The 1st smaller shield is held in with two plastic pushed in screws and a couple bolts taken off with a 10mm socket. Its the small under bumper shield that needs to be removed in order to get at the bigger shield, which is 4 pieces. You can take the big shield off in one big piece, or pretty much any of the 4 pieces. Get a lithium or air ratchet. With vehicle on ramps and on the typical DIY mechanics creeper, you can zip off all the bolts in a minute, and align/reinstall the panel in 2 minutes. Much easier when you're on a lift. Cranking with a manual ratchet/socket just takes more time. For my 2011, this shield is OVERLY complex and IMO opinion, a waste of manufacturing money.
I am glad that the oil drain plug and oil filter have access ports.
IMO, if your shield is damaged or ripped off, ANY shield is better than none. I have no problem with the flimsy aftermarket stuff. IMO, you want a shield, ANY shield, as it helps control airflow thru the engine compartment for proper cooling, and keeps all the undercarriage splash from destroying everything.
Without the shield, on a few cars, my alternator, power steering, and A/C would quick working with each puddle splash. Don't even ask about the undercarriage wash at the car wash without a splash shield. Another one of my cars would overheat without the shield. So, its not for aesthetics or aerodynamics only.