Using a graph simplifies the query parameters, reduces the need for join() operations, and allows you to reason more directly about the data model instead of rdbms concepts and SQL. Could you do it in SQL? Sure, but the bolt browser and cypher made it go a lot faster. I'd go so far as to argue that graphs are optimized for reasoning and analysis, where relational dbs are optimized for performance.

When I need a performance problem solved, I'll hire an engineer to reimplement it, but until then, I can analyze the data at the business level. Right now I just need a rope across a river to see what's on the other side and not a bridge. :)