But until/unless someone is generous on her behalf she can not fully enjoy the platform or the games she owns on it.
You mean to say she could afford the platform and the games, but not a one-time purchase of $5?
Or are you saying that some parent or relative bought her the platform and the games, but refuses to purchase a single $5 game on Steam for her?
Come on. If there is a computer gamer in the world for whom a single $5 purchase is impossible, I want to hear from them, not from someone making up a hypothetical niece who can't afford a $5 game for their watercooled i7-4550 with twin Titans.
And remember, this new threshold doesn't bar this hypothetical niece from playing her games, only from using Steam's Mod Workshop and social media services. Steam will still work just fine for playing her games.