Will I be able to get by without it? What are the benefits and are they worth the time?

Definitely worth it, if map is detailed and runs badly on laptops/low-end PCs. Increased FPS is always good

Will I be able to get by without it? What are the benefits and are they worth the time?

Im not going to pretend to know what it does as far as your pc's performance is concerned, but I had a pretty good fps increase after portalling ILS. I personally see it as a MUST do after watching vids of people play ILS before and after I portalled it. From what I do understand, if a player isn't looking into a portalled section then things in that area are not drawn, where if you don't use protals, even parts that are not seen are drawn for each player... That just seems like it is obviously better to me to portal, unless your map is pretty small where most areas can be seen at all times anyway. Some one correct me if I am wrong.

Portalling anything other than a shitty box map will undoubtedly improve performance. It's best to keep portalling in mind as you go along (like I didn't ) as this will make things easier. It's not that hard when you get used to it, but can be frustrating depending on how your map is setup. I recommend Blackjackjonnyy's tutorials on Youtube as they pretty much cover the entire process in full and explains what they do and the different methods you can use perfectly.

www.youtube.com/watch?v=YZuT3e0KcV8

yeah, its a good idea to portal, reduces overhead dramatically, bringing increased performance.

Even 2d games use a kind of portaling, only whats in your current screen is drawn to reduce overhead.

But it can be tricky. I tried it, no luck. Gonna make mr stevie here help me one day lol