1.1. Why should time zone information be preserved in a VCALENDAR object rather than converting to UTC?
1.1.1.
Recurring events that occur on both sides of a daylight savings time change need the appropriate time zone information to ensure they happen at the correct local time.
1.1.2.
Keeping the time zone information during the whole life of the event is important because it allows the events to be adjusted if a change to the time zone rules occurs.
1.1.3.
Interoperability with well-established products is a requirement for most calendar applications. Anything that those products support will most likely have to be supported by the majority of standards-based calendar applications, so we should keep time zones in the standard, clarifying them if needed instead of removing them entirely.
1.1.4.
It gives more context information about the meeting creation that can be used in the future if the meeting times have to be adjusted.
1.1.5.
Because the day of the week corresponding to a local time and a UTC time may be different, recurrence rules cannot reliably be expanded using only UTC time.
A meeting occurring every first Monday of the month at 0:30 CEST would be 22:30 every Sunday in UTC. Since the first Sunday of the month is not always occurring just before the first Monday of the month, converting that event to UTC would not expand that rule correctly.