You are simply reducing manufacturing of one type of furniture with another (that doesn't use the scraps in production) and very much increasing a lot of other manufacturing and increasing the space people need to have available to do these things.
Edit: I'll mention that many folks are simply going to buy the cheapest tools to fix stuff: A decent drill isn't cheap, but a cheap drill might get you by if you only use it lightly and occasionally. If people are using them more, I suspect more will be thrown away. At least the furniture is using some renewable products: Drills aren't made of wood and pressure and glues.
Western society has become full of contradiction...
Consumerism is environmentalism,
War is peace
Freedom is slavery
Ignorance is strength
They last decades, and can be used to repair tens of thousands of items.
To suggest that their environmental impact is higher than that of equivalent favtory equipment needed to produce furniture is delusional.