Whitespace is subtracted from the text stream. Comments are indexed separately with markers embedded into the stored text stream. If the text stream is not being sent to an edit area then the comments and whitespace are omited, reducing the bandwidth required. Scalability hopefully would not be comprimised as the ratio of clients editing content should be very small compared to the number of clients viewing content. At this time I don't understand Zope's architecture enough to know if this will be an issue.
Consistent indentation allows each coder to understand the previous editors markup.