I don't buy that. The string "Null" is different from the keyword null in programming, so `if $var = null` would be false when $var is the string "Null".
Note that when interpolated into SQL, the contents of $var must be surrounded by single quotes, so you end up with `insert into Table (Name) values ('Null')`, which correctly inserts the string "Null" into the table.
If you were to leave off the quotes, you'd get a SQL syntax error for all other people, so that code would never make it into production. E.g. `insert into Table (Name) values (Smith)` is a syntax error.
I think you underestimate how many systems are stringly-typed, not just in terms of problematic programming languages, but data traveling between different APIs or through literal dead-tree paperwork.
They don't have to all fail at null handling, just one or two can gum up the works.
Note that when interpolated into SQL, the contents of $var must be surrounded by single quotes, so you end up with `insert into Table (Name) values ('Null')`, which correctly inserts the string "Null" into the table.
If you were to leave off the quotes, you'd get a SQL syntax error for all other people, so that code would never make it into production. E.g. `insert into Table (Name) values (Smith)` is a syntax error.