>>nVarchar(100) does not reserve space for 100 chars if the contents are less than 100 chars
>
>So, basically, is it correct to assume that some might always use nVarchar everywhere and never use Char() in favor of space allocation?

No, char still has its place, wherever you need to store fixed size strings (let's say the SIN, 9 chars) or mostly the same size (let's say car license plates, 6 or 7 characters) (I know my examples are very short), if you use varchar for this examples, you are actually paying an overhead of 2 bytes per record, that is the space reserved by SQL to store the length of the actual string.