Part of the rationale behind using the zigzag pattern for linear sliders is to increase the number of capacitive pads which are activated with a single touch – and hence to increase the resolution and avoid stepped readings from the sensors.
Each pad gives us a continuous 12-bit reading depending on how much it is touched and in order to calculate the position on a slider from the raw readings of the pads it is necessary to interpolate between the readings. In effect we use a weighted average to calculate the position.
The zigzag layout makes sure that when a finger touches a particular point on the slider, the finger will also partially touch adjacent pads. This is just one pattern you could use but there have been many interesting experiments in pad arrangement to achieve similar effects. See for example: https://ieeexplore.ieee.org/abstract/document/7026172?casa_token=C4WY2QdqrNoAAAAA:NsDmkCTj0BBkXBxidP6XPh5Fb8g75pzEWEphk7M8IIsZBT1c0jdXYMMVN8upF2VwxYJlzsyl