Was it wise for Kino to throw the pearl back into the sea? Why or why not?

Yes, the pearl (or should I say Kino's possession of it) was responsible for the loss of everything important in his life. Kino, like most men, were obsessed by it. The only way to free himself was to throw the pearl back to what it came from: kind of like throwing the ring into Mordor in Lord of the Rings!