I find that when my social media usage is under control, the short down times which aren't long enough to engage in something are spent just being me, in my own head. It's rarely a transcendental experience, but I usually feel more relaxed afterwards, and occasionally I have insights on what's going on in my internal life or observations of my surroundings. Each of these moments is inconsequential, but the cumulative effect of all these moments over weeks is huge. I notice the rich life full of people and experiences that I have. I am more focused and creative. I notice problems sooner and address them. I'm more attuned with my own goals and less swayed by manufactured desires or social pressures.

My control over my social media engagement ebbs and flows. I haven't achieved nirvana. But I've at least disengaged long enough and enough times that I can see the value in the time you are talking about.