In your implementation, I am assuming that you are using CSD track-pad and not CSX track-pad.
SmartSense is just a firmware algorithm that sets the tuning parameters automatically so that it is easier to get started with the design and provide an initial set of parameters so that manual tuning is also easier.
Scanning in a CSD touchpad/trackpad happens sequentially in all devices. The rows and columns are scanned separately. The component then uses the information obtained to determine the row and columns which are active and subsequently determines which portion of the touchpad was active to determine the XY coordinates.
The issue with CSD touchpad is that if two portions of the touchpad are touched at the same time, say we touch (X0, Y1) and (X1, Y0) from figure below at the same time, then the component detects that 4 areas were touched since two rows and columns were active. This effect is called "ghost touch".
To eliminate this issue, CSX touchpad is recommended. However, if multi touch feature is not required, CSD touchpad is better since the scan time is less in CSD touchpad.