Attaching Pistol Grip- Brass threaded inserts or tapping threads?

First ever build was the Spectre SI15. Build guide said to melt a brass threaded insert into the lower. That way the pistol grip would be screwed into metal instead of plastic.

Reading the Ubar3 guide, Ivan chose to tap threads into the lower. I trust Ivan’s judgement because he’s been polishing the ubar for 10ish years. In my mind though… the brass threaded insert seems like it’d be stronger since it’s metal on metal. Harder to strip out the threads etc.

Thing is.. with Ivan’s method you can use the actual screw that’s meant for the pistol grip. If you use the threaded brass insert. It’s a much smaller flanged screw. I’m not sure what to think.

Would appreciate thoughts/advice.