Taken from the **freedesktop.org** site:
> The actual nuts-and-bolts distro tool (dnf, apt, etc) is used by PackageKit using compiled and scripted helpers. PackageKit isn't meant to replace these tools, instead providing a common set of abstractions that can be used by standard GUI and text mode package managers.
I've personally never had issues blasting this out (in fact, I do it on almost every clean install of Fedora). **However** , the sensible answer would be to use your system with it disabled for a while, and then uninstall completely once you're sure nothing breaks.
Link to more info on PackageKit: link
**EDIT:**
Found this in the FAQ as well:
> **Can users still use their normal package managers and backends, such as Yum, APT or Conary?** _PackageKit does not stop you using the low level tools, in fact it quits as soon as possible if a native tool is waiting to be run._