Updating values may or may not result in links being changed. For example if you imported data where 'Illinois' was misspelled as 'Ilinois' for the 10,000 customers who lived there; updating the value to the correct spelling might not change any of the links.

All the links are stored within a hashed set of data blocks where similar links are stored near each other. This helps minimize any write amplification. You might be able to update 10,000 links while only needing to write out a few blocks to disk.