Floating node in 4T CMOS camera pixel
A charge transmission phenomenon is not a feature that differentiates CCD and APS devices. A photodetector used in CCD and 4T APS image sensors is the pinned photodiode (PPD), and in PPD, incident photons do generate charge in the pixel photodiode that is later converted to a voltage signal.
In 3T APS cell the photodiode is not pinned and connected directly to the output buffer (source follower). The Wikipedia article explains the advantages of photodiode pinning:

The pinned photodiode, when coupled with the transfer gate, allows
complete charge transfer from the pinned photodiode to the floating
diffusion (which is further connected to the gate of the read-out
transistor) eliminating lag. The use of intrapixel charge transfer can
offer lower noise by enabling the use of correlated double sampling
(CDS).

In a 4T APS cell, the charge from photodiode is transmitted, via a TG transistor, to the source follower transistor's gate and only there the charge is &quot;converted&quot; to the cell's output voltage \$V_{out}\$ to be read by the readout electronics when the cell's row and column are selected. The transfer physics of carriers from the PPD is similar to CCD charge transfer (page 38; 6/11 in pdf doc).
Consequently, the further improvements of fixed-pattern noise (FPN) figures are connected mostly with PPD design solutions, as a fabrication of a p+ layer surrounding the shallow trench isolation sidewalls in order to isolate n-type buried signal charge storage well (&quot;floating node&quot;). You can read about the development of PPD structures that resulted in low noise, high quantum efficiency and low dark current image sensors, both CCD and APS, in the IEEE Journal article A Review of the Pinned Photodiode for CCD and CMOS Image Sensors by Eric Fossum, a creator of APS device.