Every Repeat Customer Insights account can now have unlimited users without needing Shopify accounts for each.
Previously, in order to use the app you'd be required to have a Shopify account to login. That's fine for staff but what if you wanted a consultant, advisor, or investor to see your metrics? You'd have to give them a full Shopify user account (and might have to pay Shopify for that account) and train them on how to get around Shopify's admin area.
Now any person can be invited by the account administrator to use Repeat Customer Insights without needing a Shopify account.
If you have multiple accounts, you can even invite someone to each of your different stores. I use this myself to make it easy to switch between my various Shopify stores.
If you haven't installed Repeat Customer Insights yet, it's a quick and automatic way to measure your customer behavior.
Get a snapshot of your customer behavior
The sooner you signup for Repeat Customer Insights, the more comparison points your store will have. Each 1st of a the month a new snapshot is taken and saved to your account for analysis.