Most MMOs 'benefit' from spreadsheets and APIs. Any situation where players are incentivised to optimize/track/gather statistics benefit from them.
Guild Wars 2 is an example of a very casual MMO that nevertheless has an extensive API, and a wide range of fan-built sites that use it to optimize/track history of trades, manage your account, track achievement histories, improve wiki information, etc.
Guild Wars 2 is an example of a very casual MMO that nevertheless has an extensive API, and a wide range of fan-built sites that use it to optimize/track history of trades, manage your account, track achievement histories, improve wiki information, etc.