Aye; there's the rub!
The “where required” can either be when required by law or more importantly imo if one doesn’t honestly have the skill to DIY. You should see the stuff I see from DIY selfers let alone hack electricians.
Another thing about using skilled tradesmen, you’re employing a fellow American, you’re supporting Main Street USA not Wall Street.
Most tradesmen use American made tools and install American made products, so yeah they might be more expensive but you and they are not supporting China.