Before Newton unified terrestial and celestial mechanics, you needed to keep them separate whether you were using a geocentric or a heliocentric model. You still needed a sublunary sphere sphere around the Earth where things slow down and fall and break and decay on their way towards the End of Time, while God and the Angels watch us from their perfect and immutable Heaven. Neither the geocentric nor the heliocentric model had an advantage in terms of explanatory power here.

If the earth has a sublunary sphere, that suggests the earth is 'special', which is certainly more parsimonious in a geocentric universe. Also why doesn't earth's sublunary sphere cause it to fall into the sun?