Talkback builds - are they any use?

I don't know if it's even worth asking here, but:
   do the talkback builds provide worthwhile data?

I also notice that they only seem to exist for the pre-release versions 
of Mozilla.
Why not have a talkback build for the current stable version(1.5) ? The 
crashes which come from those are undoubtedly the most difficult to 
track down - or else due to hardware, etc.


Sorry about the lack of email address, but in view of all the nonsense 
in this group...

Charlie