there is one very big advantage of having a cellular ipad specially if you travel alot and take pictures frequently because most of the wifi nearby is password protected and you might want to use social media instantly. lets say your traveling to other places and take pictures stay in a hotel and hotel wifi is very expensive every night so its worth spending the extra on the cellular version ipad and its worth paying $10 to $50 monthly on cellular depending on your carrier and plans you choose rather than spending $15 dollars for slow wifi per night at the hotel because you buy a wifi only model. wifi only models are suitable for people who dont travel much and for people who might not be interested in photography or take photos casually, but on most smart phones you have the tethering option just in case.
all in all, in your position i highly encourage you to invest on the extra cellular capability and a monthly data plan for extra convinience and security. thanks for taking the time to read and taking my advice, sincerily joan.