TemplateHaskell: why is PprSplice much faster than DumpSplice?

TemplateHaskell: why is PprSplice much faster than DumpSplice?

$ make benchmarks/prof-time b=Brainfuck/ByteString/hanoi/SymanticParser.PprSplice
benchmarking Brainfuck/ByteString/hanoi/SymanticParser.PprSplice
time                 71.19 ms   (69.66 ms .. 72.58 ms)
                     0.999 R²   (0.999 R² .. 1.000 R²)
mean                 71.91 ms   (71.10 ms .. 73.18 ms)
std dev              1.755 ms   (973.5 μs .. 2.766 ms)

$ make benchmarks/prof-time b=Brainfuck/ByteString/hanoi/SymanticParser.DumpSplice
benchmarking Brainfuck/ByteString/hanoi/SymanticParser.DumpSplice
time                 170.5 ms   (169.7 ms .. 171.0 ms)
                     1.000 R²   (1.000 R² .. 1.000 R²)
mean                 169.4 ms   (168.3 ms .. 169.9 ms)
std dev              1.046 ms   (375.5 μs .. 1.650 ms)
variance introduced by outliers: 12% (moderately inflated)