You are right that side chain and rollups both act like Load distribution element at blockchain. This is I am saying that if I talk about specifically side chain then from main blockchain it moves transactions. In this way load becomes reduced from main blockchain.

If I talk about rollups then they are just like 100 in 1. I mean to say that it combine multiple transactions into one single roll so beautiful different transactions because less storage of data which is a plus point.

Good luck 🍀