Per rfc8806, because the data in the root zone has long TTL values, most queries to the root servers are for nonexistent top-level domains due to typos and search paths gone wrong, so in some sense it's community service to reduce useless traffic to the roots -- you do a single burst download of about 2MB daily instead of all of your query traffic.

Other reasons why you might do it are covered in rfc8806 - slightly reduced latency on cold-cache DNS queries, added resilience against DoS attacks against root DNS servers.