It merely consists of the general observation that shell scripts with lots of backticks in them are often possible to optimize and clean up a lot. Obviously, backticks are a valid construction, and you can put them to good use in many shell scripts. I have simply noticed that newbie scripters often generously treat backticks as the hammer for all those nails they see. The classic example is running something on each one of a number of files listed by find . An additional problem here is that find might find files whose names contain line breaks.
GNU find can even cope with that, by using the null character as the file name separator.
With normal find , a user could create a file with a newline in its name, tricking you into, well, at least missing that file, and potentially something a lot more dangerous. In case something is still not obvious, the only disallowed file name characters under Unix are the null character and slash. Awk scripts that are basically cut unless reordering of fields is needed. Complex schemes to basically eliminate certain chars. For example DOS lines to UNIX lines.