DISCLAIMER: I'm not very familiar with Cauzzy (I've heard of it, and heard good things, but not used it myself)
But I think that NetSuite adding this MCP server / custom tools is a nice step, but far from a full blown solution.
I'd say that there is still room for Cauzzy (and other services) for the reasons you just listed. There is still value to providing data more efficiently / more accurately.
I'm sure I could get the NetSuite AI connector to get to the right numbers, but it may take 10+ iterations of it trying to write the correct query, which is slow and leads to distrust for users. (and a bad UX)
I see a future where companies are selling "pre-built custom tools" that can detect prompts and know exactly what queries need to run.
I just built a Custom Tool called "Run Flux Analysis".
It can take a users prompt of "Run Flux Analysis for Q2 2025" and it runs a set of queries and generates a full Flux Analysis report. It's specific the company that's using it, but it's scalable in the sense that they will be able to use it for every quarter moving forward.
This feels like the beginning of NetSuite adding SuiteScript again.
Companies know what they may want from AI interactions, but there is still room for developers to develop custom tools to get the users the exact data / responses they want
(just my 2 cents)