I always fly business or once-in-awhile, first. I have no tolerance for the nonsense people demonstrate on flights (and 'nonsense' is a polite word).
It's not 'extra leg room'. Your seat(s) turn into a bed. You sit in a 'cubicle', so you don't have anyone in your 'space'. You can actually sleep on the plane without anyone 'elbowing' you or eyeing you. The 'cubicles' have glass dividers that you can raise or lower, so you can have close to total privacy (I say 'close', because if you take an aisle seat, you can see across the aisle. If you're on the window, you have total privacy. Your seat comes with pillow, blanket, headphones, eyemask, and toiletries. And, of course, no problem with getting an overhead bin as there is far more room than people have luggage. People stuffing oversized bags into bins half the bag size is another of my pet peeves with the flying unwashed masses.
I make the trip into a total indulgent outing. I go to the airport early and have a really good meal in the business class lounge. There is endless food, drink, snacks as part of the lounge experience. I enjoy sitting in the lounge, before the flight, reading or watching the 'tube' if that works for you. This is all included with your ticket (just to be clear, I'm not getting drunk and getting on the plane as some do). Then, the meal, and the liquor on the plane, are all 'gourmet' (of course, how good it is can always be argued -- we all have different tastes). And, of course, I do the same thing on the return flight.
And yes, you get more than a 'little more deference' from the flight crew, if you wish. You have a lot of crew for relatively few people. That may or may not make any difference to you.
Now, as you know, the difference in price is enormous. Only you can decide if it's worth it to you. If you're not aware, you can look at pictures, and video, online, showing the features of business and first class seating. You would need to know the model of the plane you would be on for overseas to get the right pics. More than likely, it would be one of the 777's, possibly model 300.
My perspective is that wife and I scrimped, saved, invested for 40+ years. We have the financial means to 'indulge' after decades of camping and staying at Motel 6's.
You'll have to determine your wants and what is 'worth it' for yourself. Good luck.