Originally Posted by
pattern_is_full
Type designators are used for planning by airports and fire services (ARFF), as well as ATC.
I'd guess any notable changes in characteristics or dimensions such as weights, door heights, engine ground clearance (e.g. neo and Max), sharklet-heights, fueling points, internal aisle widths, etc. are going to be worth flagging for those ground planners.
Even if they are unimportant in 99.9% of ground operations, there may always be one gate somewhere where the little differences could result in a ripped sharklet or a dented nacelle, unless designated.
All true, although many of those distinctions (sharklets, internal config, etc) are catered for by different IATA codes while still using the same ICAO designator.