Well, no; the entire point is that there are multiple ways to interpret the Template in context. One possible application is for localization (supposing that the interpolations are objects that can give a localized string on demand, or e.g. integers to be formatted in a locale-aware manner). It should probably be possible to do that with .format anyway, but just as an example. Perhaps someone out there wants to store fragments of SQL within a JSON document, too. The point is to maintain that flexibility, by separating the parsing and formatting steps.