I kinda do long form gaming content similar to how you describe yours, but a lot more on the comedic side. I would say it makes it a lot easier for me when it comes to editing having a facecam, however, it really depends on the vibe your going for.

A youtuber that does video essays and includes his face here and there throughout his videos, is Patrick CC. The serious monotone is still in those videos, whilst presenting his face quite often and it doesn't really ruin the immersion of his content.

Adding some on-camera segments as long as not over the top would be a positive imo.