Why is scaling layer 1 chains important?

If I understand correctly, Marlin is attempting to scale layer 1 blockchain platforms. Why is it so important given several layer 2 solutions based on state channels, optimistic and zk rollups are taking shape?

Due to the tradeoffs L2 makes. These posts by Vitalik get into some depth.

Also relevant: https://twitter.com/VladZamfir/status/1001447804219346945