Question regarding DNS and Route 53?

Hey Guys,

So I'm a bit confused about DNS and Route 53 and it's use cases. My understanding is that DNS servers are lookup tables where you can put in a URL and get the corresponding IP and vice versa. It's something used by ISPs to convert www.google.com to the correct IP address.

However, Amazon seems to be offering Route 53 as a service to developers? Why would a developer need DNS services (isn't DNS being taken care of by their ISP)? With regards to a company, why would a company need DNS for their web server? Isn't this something that only ISPs would need / use? Thanks.