For me Audacity is only good for editing samples/sound
files.
Using it as the many HDR for your DAW is not an option (yet). Lack
of realtime effect sends, bussing, automation, etc. would make it
difficult for me to suggest to anyone to use audacity as the center
piece to their DAW.
That depends what your needs are. If using an analogue mixer with
outboard effects, for example, you may not need these features within
the software. Many kinds of music don't require heavy effects
processing or editing, such as the live acoustic material I'm
recording this week.
(One of the best selling records last year, by the White Stripes, was
recorded on analogue tape with no automation whatsover...)
Many musicians use 'portastudio' devices because they like the
simplicity. I'll go for something that 'just works' over
feature-packed bloatware any day.
Cheers
Daniel