Not exactly convincing:

    ~/desktop$ du -h c.dat
    11G     c.dat
    ~/desktop$ time cat c.dat | awk '{ print $1 }' > /dev/null
    
    real    0m53.997s
    user    0m52.930s
    sys     0m7.986s
    ~/desktop$ time < c.dat awk '{ print $1 }' > /dev/null
    
    real    0m53.898s
    user    0m51.074s
    sys     0m2.807s

cat CPU usage didn't exceed 1.6% at any time. The biggest cost is in redundant copying, so the more actual work you're doing on the data, the less and less it matters.