The question 'Do I Need Final Draft' is from @CraigJBeadle.
If someone who's paying you proper money for a script says you need to buy Final Draft because their whole production system uses it, you should probably buy it. It's really not that expensive in the grand scheme of things and it is one of the tools of the trade. You wouldn't want a plumber turning up to your house with a proper toolkit, would you?
But it's not necessarily an essential tool. I only got it about ten years into my writing career when I was working on Bluestone 42 in South Africa. Our production partners, Out of Africa, used it and to make life easier, it made sense to have the same system as we were making changes on set. But the entire first series of eight episodes had been written in Microsoft Word. As has every single script I've written for radio.
The reason people feel they should buy it is because it will make them feel like a proper writer. And, to be honest, if you need a £150 for a morale boost, then there are worse ways of spending your money. But the programme itself really isn't all that brilliant. It's pretty sparse and not especially intuitive. I don't hate it as much as Craig Maizin does - and you can listen to him talking to the creators/owners of Final Draft on the Scriptnotes podcast here. It's great listening.
I think people tend to focus on script software and the look of their scripts because that's something that's easy to control and measure, as opposed to whether the script is any good. When you're starting out, it's hard to know how you're doing, so you want to at least look the part. I'm not saying that's you, @CraigJBeadle, but it's a factor. Hope that helps.