Agents in the cloud (and locally) need to have a full repo, even if they only need a small percentage of a repo to make a change. You can also imagine if changes are being made in the cloud by multiple agents, each one of these agents need a shallow clone at the very least. If you're spinning up many agents in the cloud this becomes a bottleneck. So not really that downloading things is a bottleneck, it's that agents need to download way less to make the same decisions and changes.