Is it ever completely necessary to get a bone graft after removal of impacted wisdom teeth? (Photo)

I need to get all my wisdom teeth removed. My bottom two are really impacted, and angled. After looking at my x-ray and ct scan results, my oral surgeon decided bone grafts were needed on my bottom two and guided tissue regeneration (think on my top two because of sinus exposure) costing $2100. The oral surgeon refused to proceed without these procedures. I've gotten a referral to a different surgeon who said they would. I want to make sure I'm making the right decision here, can't afford $2100