unset GHC_PACKAGE_PATH for cabal-install

[Mekeor Melire]

How to use cabal-install in GuixSD? `cabal install` leads to an error
saying its incompatible with GHC_PACKAGE_PATH variable:

$ cabal install hascal
Config file path source is default config file.
Config file /home/mekeor/.cabal/config not found.
Writing default configuration to /home/mekeor/.cabal/config
cabal: Use of GHC's environment variable GHC_PACKAGE_PATH is
 incompatible with Cabal. Use the flag --package-db to specify a
 package database (it can be used multiple times).

So, my question is: Is it fine, to just temporarily `unset
GHC_PACKAGE_PATH` variable before running cabal-install? What's the
disadvantage?