Marble statue of a young Hercules. MET Museum, NYC, NY.
Understanding what other artists' materials and processes are, gives a great understanding into one's own creative process. Thankfully we have museums whose goals are to collect, restore, and make available art that has been produced for thousands of years. We probably only get to see a sliver of the holdings of a museum at any one time and then again only a small slice of works which have survived to this day.
For me, visiting a museum is like visiting friends in a foreign city. Its always a pleasure to see them again, to look them over and study them as if new to my eyes but with the added value that I have already spent time closely looking at these works of art before.
I know that I am not alone in this feeling. You can visit a museum any time to see the hundreds if not thousands of people who come from around the globe to see and study a museum's collections and shows. More the reason to encourage individual collectors to turn their collections over to large and trusted institutions for safekeeping and public display.