It would be nice if the default examples in /etc/crypttab use /dev/sdaX instead of /dev/hdaX because as far as I know most users are using the sda pattern.
Distracted users (like me for example) are maybe just editing the number of the partition to use and uncommenting an entry and they are going to run into trouble because they did not recognize that crypttab uses the "old" hda pattern. If you are having problems with mounting of non-existing hda-devices because you forgot to change hda to sda, even the systemd logfiles aren't a good help for finding the source of this silly problem so changing the crypttab would maybe help to avoid problems.

I attached the crypttab as it is distributed in the filesystem package and how it could look like if you accept my concern.

Michael Eder