wawrzon, I suppose no one really NEEDS a new AmigaOS computer if you get down to it. Except... I need one with every fiber of my Amigamaniac being. :-)
OK, want is the more proper word than need. I want it and have it, and I use it every day to do all sorts of fun things. I enjoy the operating system and appreciate that is has been updated and is being improved without losing its identity. I recognize it as a continuation of the same OS I loved from the Commodore days. I love that it can run a mix of old and new software. I don't play games very much at all -- never did even when I got my first Amiga computer in 1987. But there are new and old games. I spend a lot of my X1000 time using IRC clients, email and our growing list of Web browsers. (The Odyssey port from MorphOS is outstanding.) It's great using and seeing new original AmigaOS applications like Andy Broad's SketchBlock mature, and Lyle Hazelwood's Score is going to be a lot of fun. The Blender port can do a lot of stuff. But what made me jump onto the bandwagon for the newest AmigaOS versions is seeing Elwood's YouTube videos showing how well version 4.1 can run a lot of the great old Amiga creative applications -- specifically LightWave, ImageFX and TVPaint. His videos show these programs running very well on a Sam440ep @ only 667mhz! I have that same machine (times two) and also an X1000. Since then, I have also learned firsthand that I can also still use Photogenics, Wildfire, Imagine, VistaPro, Perfect Paint, Personal Paint, Milky Tracker, HD-Rec, Audio Evolution, etc. etc. etc. as well as mess about with handy new tools such as VideoClipper, ffmpeg, etc. Hollywood with Hollywood Designer is AWESOME.
So in short, there are lots of things to do with a fast, capable computer that can run AmigaOS in its current version. I haven't run out of ways to have fun with mine yet.... and it will get better as software development pushes forward.
Yes, it's expensive. No, you might not think it's worth it for you. That's OK. I see people spending money all the time on stuff I wouldn't buy.