I agree. The first point in particular is a very selfish way to look at social interactions. I think most people would be uncomfortable knowing that there could be an unlimited number of invisible participants in a conversation especially if it was in a VR space where you feel much more present than in a chat. It's also not very pleasant to have someone who you didn't know was there to suddenly jump in on a topic unexpectedly. Having your avatar there as a placeholder that others can acknowledge is important for that reason, you aren't surprised when a quiet person chimes in on a conversation since you are aware that they have been listening and could speak at any time. An invisible ghost jumping in on a topic would be jarring to say the least.

As a socially awkward person, I understand their difficulty with being present and not speaking. The only advice I can offer is to learn to be comfortable with that discomfort, not very helpful I know. Most people are accepting of quiet people just hanging out and occasionally contributing, there's no need to hide.

Alternate input is tricky especially when we're talking about a multiplayer experience like Poker Stars VR. If they did allow you to interact solely with button pushes, what would the other participants see? Some default set of animations? A big part of the experience of that game is the social interactions around the table. Turning to speak to the person next to you, playing with all of the props provided in game, telling jokes or stories, etc. It's like a real poker game. The author seems to want a 2d experience instead so my question is why are they even bothering with VR? Why not just buy a headset that is designed as a heads up display and play regular pancake content?