Unfortunately for my explanation, it doesn't seem to make much difference on this case. In the second form the reverse is true. I believe this observation about the respective strengths and weaknesses of the two kinds of notations goes back to Alonzo Church, the inventor of Lambda. The quasi-parser sees the string without the embedded expression source. Except for the embedded holes, it takes the input text to just describe itself.
Substitution consists of stringification of the value, and string substitution.
Modulo some security issues beyond the scope of this overview, quasi-parsers should therefore cache ValueMakers by transformed string. It takes an expression on the left and a pattern on the right. If its value is true, then the such-that pattern as a whole succeeds. Matches a list of the same length by matching each element against the corresponding pattern. Except for holes, all characters just represent themselves and must match exactly.