You can't mine stone with stone pickaxe?(or stone tools) So What's the use of stone tools if so?
There's no information about the changes to stone tools and interactions. What other changes were there?

This mod disables the functionality of wood and stone tools by default, but you can enable them again if you want by opening:
.minecraft/config/earlygame.json

Look for the crafting section of the file and set enableWoodenTools and/or enableStoneTools to true.

You can download Mod Menu if you want more information about the configuration.