You still need Portals in some instances.
I find instant load and unload handy if you want to run a session without configuring all the industry tracks.
For instance you might have rolling stock scattered around your route at various industries or in yards. You can create a daily freight service that goes around and picks up and drops off wagons. You can use your locos to shunt the wagons to the industry or have a shunter loco, then select 'instant load' to load the first item in the unit's config. ( I have cloned wagons set to load different loads).
When you get to the destination select 'instant unload' to drop the load.
This gives you a dynamic session that can go on for a long time without too much setting up of industry tracks.
Cheers,
Mike.