Special plants like skid applications can be very beneficial in certain situations. Configurations can be pre-installed in advance before the actual installation with only the final touches on-site. This portable method allows for installs in time-restricted areas or with difficult and special access.
The container application is great for limited space inside the premises, this can be even a hybrid install where a certain % of the system is outside in the container while the rest is inside. As with the skid application, this can be pre-installed to a certain degree depending on the application.