Hello @M1che1,
the Unipi 1.1 has been designed for needs of Raspberry Pi 2. Since then, the RPIs got more power hungry and the internal connections might not be suitable for powering both the RPI and the Unipi 1.1. That depends on what RPI you are using and what you are running on the RPI. It is definitely safer to use separate power supplies.
Best regards,
Martin