in an ideal current driven phono stage that uses an op amp to sense current, is the coil of the cartridge connected to that virtual ground that you describe? One end of course. If that is the case, where do they connect the other end of the coil?
Ground.
The result of this experiment was interesting. Even thought the gains of both situations were the same, the 4.7kΩ load through the 1:8 sounded a good 2dB louder. When the gain of the 2.2Ω load was bumped 2dB suddenly it was preferred and then going back to the 4.7kΩ 1:8 at the same +2dB level started to hurt my ears.
Transformers transform impedance. Further, to prevent ringing they must be properly loaded at their output, to something called 'critical damping' where a squarewave input to the transformer results in minimal overshoot.
If not loaded the transformer can 'ring' with excess harmonics- its making distortion. Your ears will respond to that as sensing it as loudness and yes, it might even hurt if the volume is up a bit.
Because transformers transform impedance its not necessary to load the cartridge directly with a low impedance in order to achieve a low impedance- you can do that on the output side of the transformer as well. IOW putting a lower impedance load on the output will reduce the load impedance the cartridge sees. This is because the only isolation a transformer offers is galvanic and DC; it does not offer impedance isolation.
This loading issue is one reason I avoid SUTs- you do have to manage their care and feeding. If the SUT is designed for a specific cartridge, the correct load is probably 47K (but will be different if a different cartridge is used). Its really important to keep interconnect cable capacitance to a minimum. But if you simply have enough gain and your phono section has no worries with the RFI that will be generated by the cartridge/cable interaction, then you have no worries- its plug and play.