While installing an extension from CLI, if an extension is already installed, CLI reached to Marketplace to check if there is a newer version or not and prints following message:

Extension '<extension-id>' v0.20.0 is already installed, but a newer version 0.21.0 is available in the marketplace. Use '--force' option to update to newer version.

Though informative, it is not necessary and makes the operation slower. At the end --force flag has to be passed to forcefully install/update.

To make it faster, do not reach to Marketplace if extension is already installed. Check and install updates only when --force flag is passed.