Pixels doesn’t let you play endlessly. You actually run out of energy. Every action drains it!
- farming
- mining
- even simple stuff like planting crops
At one point, I burned through my energy just watering crops and suddenly my character slowed down like it hit a wall. 
That limitation changes everything.
You can’t just grind non-stop like other games. You have to plan. Decide what’s worth doing now and what can wait. Energy becomes your real currency, not just tokens. 
This is actually intentional
They even reduced energy regen in updates to make things slower and harder, mainly to stop bots and reward real players. 
Imo, this is low-key genius. It forces patience and forces decisions.
Pixels isn’t testing how fast you can farm.
It’s testing how well you manage limits.