Tying DGND to VSS on AD5252


I am planning to use the AD5252 and AD5254 on a programmable filter and interface the components using I2C with an Arduino Nano. The filter supplies are bipolar VDD=+2.5V,VSS=-2.5V.

I was hoping to use the same supplies to power the Arduino by setting its ground to -2.5V and its the Vin pin to +2.5V.

My question is: What drawbacks would I face if I tie the DGND pin on the digipots to VSS (and the Arduino ground) and interface with the Arduino that way?.

In general, is there any significant drawback to having the digital and analog grounds at different levels? (In this case AGND=0V but DGND=VSS=-2.5V)

Thanks in advance for your help.