Currently, the trigger to add a chip is ENTER keydown event. I think it's a good idea to add custom keycodes that would trigger a new chip. For email chips - "," " " are useful triggers.
Here is the use-case:

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This is a fair proposal. Will try for the 1.0beta.
I would very much like this, too.
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For regular chips this can be done using md-separator-keys. For contact chips, there is an active PR (#8142).
Pull Requests would be welcomed.
There is already an active pull request for md-contact-chips. For md-chips it's already implemented.
@Frank3K - PR #?
This issue is closed as part of our 鈥楽urge Focus on Material 2' efforts.
For details, see our forum posting @ http://bit.ly/1UhZyWs.
This is only open to track the support in contact-chips which has an open PR https://github.com/angular/material/pull/8142.
Support for this feature already exists in regular chips.
Contact-chips support PR merged in https://github.com/angular/material/commit/eb10b56cbc29e59c669076142cf0a91e1d84d175.