Integrating CTAs to Outlook/Google calendar may have seemed like a great idea, but the execution misses the mark as it maps the entire CTA to a single day, whereas there may be multiple tasks associated with a CTA with different due dates.
CSMs loved the ability to view their Cockpit in calendar form from within Gainsight, and to this day still complain that (in addition to the point above) their Outlook/Google calendars are already cluttered with internal and external meetings, and makes it difficult to truly see what calls to action are on their plate day over day.
It also requires them to set up the syncing to the calendar via automation (which if not careful can OVERsync) or to manually sync CTAs over to their calendar, which takes more steps to complete rather than simply having a calendar-based view directly in Gainsight. The calendar-based view also made it easier for CSMs who are covering for another person out on PTO - they don't have access to the absent CSMs calendar.
The CSMs work their action items in Gainsight, so the CTA calendar solution should live in Gainsight. CSMs track and schedule their meetings through Outlook/Google Calendar, so it makes sense to have an integrated solution there like Gainsight Home Calendar.