The problem with most auto-escaping templates is that they may save typing (by turning on escaping by default, rather than making developers do it explicitly),

The problem with most auto-escaping templates is that they may save typing (by turning on escaping by default, rather than making developers do it explicitly), they don't save thinking. You still need to inspect each template and make sure that the correct escaping is used for each interpolated string. Context-aware systems like this one (or others that operate directly on structured data rather than strings) allow you to rely to a much greater extent on the computer for that work.