The conflation of empty string with a real null isn't great, but it doesn't also imply conflation of the string "NULL" which is what I'm trying to figure out. The four-character sequence shouldn't ever be considered something other than a four-character string, except for particular non-user-facing situations such as when actually writing code. Even spreadsheet software, which does all kinds of heuristics to find numbers in strings for example, doesn't treat the string "NULL" as anything other than a four-character string, to my knowledge.