As far as I know, you have to be experienced in programming and Linux in order to manipulate it the way you want. It is good for home improvement and some fun projects.
Yes and no.
With a basic Raspbian install, you can use it as a simple/cheap desktop without much in the way of expert knowledge. Desktop Linux is not really that much different from Windows or Mac. And as long as the application types you need are already there, you don't need much knowledge.
As an example about 10 years ago, my Mother-In-Law wanted a PC after she retired. Her only exposure to computers was Windows at the Solicitors office where she worked for the previous 5 years, and that was only doing basic stuff, but she wanted to do email and some photo stuff with her new digital camera.
We got an old PC out of my garage, replaced a few components on it and installed a Desktop Linux distro. Set a user account on it, configured it so we could remotely log in and administer it, and handed it over with about an hour's tutorial. She used that computer for about 6 years for writing letters, email, Facebook, and photo management with no major issues or difficulties until the motherboard started to die.
That PC was probably about as powerful as the Raspberry Pi 3.
On the other hand, she didn't do anything advanced with it like video editing or audio recording.
The biggest issue with the Raspberry Pi is they have a different internal architecture to typical desktop/laptop PCs and that means that any software has to be ported to them. That's not always easy, especially when you are talking about applications which touch the hardware in a significant way (like audio I/O does).
You probably *could* run audacity and other applications on it, but it's not going to be as easy as running them on a normal Linux desktop PC, unless someone has already done the work for you and packaged it up in a way that makes it easy to access.
So, not recommended unless you like to play with this stuff.
Cheers,
Keith