The engine coolant doesn't care for electrical properties. The battery is highly sensitive to that. The engine coolant just needs to absorb and release heat, while not damaging the engine. The battery coolant needs to do all that, and also not conduct any electricity.
You're welcome to not replace it, but if it's under warranty and you need a claim, you have forfeited that.
Is it worth it? Up to you.
Just like my engine oil looking brand new after 2 years. Did it absolutely need replacing? Probably not. But to maintain warranty, you have it changed every 2 years. When the warranty is done, go wild. You're paying for any repairs anyway, so do what you feel is best.