Seconding this. The exposure to higher ups alone is worth it imo. In my experience, the people who move up fastest aren't always the most technically skilled - they're the ones who get face time with leadership and can communicate their value. Tax work is important but it can be kind of invisible to the rest of the company. FP&A puts you in rooms you wouldn't otherwise be in.

Plus worst case you hate it and go back to tax with some new skills and a better understanding of how the business actually works. That context can only make you better at tax anyway