I would like to use Google Chat as our inter-company and client / partner hub for quick communication. Email is still relevant, but the majority of communications today, take place via chat applications both on my pc and on my phone. However, for our needs, it is essential that the process for external users to join via invite is critical. If they are required to create a new Google account, this is a substantial barrier and may make things more difficult than the alternatives such as Slack or even RocketChat.
In all chat environments, there is an account creation requirement, but the process for those other applications is much easier and does not require a gmail account. For a business trying to communicate with clients, leads, partners and vendors, not all of them use Google and many of them do not want to be required to create a Gmail account. I would love to see a simple registration process specifically designed for Google Workspace Chat that allows external users to participate. Without this, the tool is not viable for us.
This capability already exists in principle, by creating a Google account without a Gmail address. One can create a Google account with an existing non-Google email address, for use just as you suggest, simply for Chat.
ref: Google Support: Create a Google Account ~ Use an existing email address
In my experience, client companies do not want to have to create any type of Google account to participate in a chat. It is not the friction of creating an account, it is the confidentiality issues that a 'public' google account poses.
To my knowledge there isn't any Google designation for a "public" account. Google has internal and customer accounts. The customer accounts consist of consumer accounts (what might be referred to as "public"), usually in the gmail.com domain or some other domain, (using a non-Google email address), Workspace domain accounts, and Cloud Identity accounts. Google Security and privacy with all of these accounts is almost second to none in the industry. As accounts, of any of these types, can be created with ambiguity (non-specific user name), there is no confidentiality issue when using the Google Chat service.
It is not the friction of creating an account, it is the confidentiality issues that a 'public' google account poses.
What do you perceive as the difference between making a Slack/RocketChat account to a Google Account for an existing email address?