Worth is something only YOU can determine.
Yes, a 3070 is a faster graphics card and your psu can support it.
If you play fast action games or run at higher resolutions, the upgrade is likely to be a good one.
But, take the time to verify that you can benefit from a stronger gpu.
Run this simple test:
Run YOUR games, but lower your resolution and eye candy.
This makes the graphics card loaf a bit.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.