There are better players out there for pretty much every position in the team (we did have the best keeper for a couple of years mind) the question is how attainable/affordable they are and how they fit into our team and the manager's way of playing.
There are strikers with a better first touch, others with a better finish, but Watkins tops other metrics, like work rate, movement, fitness to play, team ethic. There are very, very few strikers out there (I would say if any) that would offer the all-round game that Watkins gives us, that would also score more goals and create more chances for teammates.