You walk everywhere when you are on a boat vs driving when you are living on land. To get groceries you walk, to get parts you walk, to do laundry you walk, most everyday you are walking somewhere to get something done. Having good shoes that are able to be used for walking in sand, mud, gravel, or pavement is needed because you don't have space for option. You probably have a good pair of flip flops or water shoes but for your heavy duty walking nothing beats a good pair of sneakers.
On land having several pairs of tennis shoes; old ones for working out side, ones that are good for walking, ones that are good for colder weather, ones for going to work in and basketball shoes isn't as big of a deal because you have the space. As a side note if you want some really really good sandal go look at OOFOs, https://www.oofos.com. I have a pair that I have worn for several years and have promoted them to friends and they have not been disappointed. Just recently I walked my good walking shoes out of their soles and it was time for a change. The old ones went into the trash and the new ones are being broken in, lots of walking to do ahead.