Current-domain vs charge-domain
Two implementations
Both share the charge-domain advantage (precision, linearity, low static power); they differ on the storage element (dedicated non-volatile device vs standard volatile SRAM) and therefore on density and process complexity.
The catch
Charge-domain makes the multiply nearly free, but the result still has to be read out of the analog domain into digital — and the analog-to-digital converters do not get cheaper just because the MAC moved to the charge domain. The ADC Bottleneck (analog in-memory compute) is the binding constraint on all analog CIM, charge-domain included. Charge-domain moves the energy bottleneck from the array to the periphery; whether it removes it at scale is the open question.