Tying cables together is a good practice as it provides a clean mechanical design

You can create a clean mechanical design by tying cables together, however it can also disrupt your product’s operation. There are multiple methods to provide interference between cables: resistive, capacitive and inductive coupling. The 2 last options depend on the distance between the cables. Communication and analog lines are often very susceptible and power cables can emit large EM-fields. So intelligent cable segregation is important to prevent self-disturbance within your product. In IEC TR 61000-5-2 multiple cable classes are described going from highly susceptible to highly emissive, together with minimal spacing to prevent EMC problems.