What is the difference between `current-word' and `word-at-point'?

[Marcin Borkowski]

Hi all,

it seems Emacs has two functions with a very similar purpose,
`current-word' and `word-at-point'.  I understand some obvious
differences (like that `current-word' can treat "symbol" characters as
constituting a word or not, and `word-at-point' can give the current
word with the properties), but does anyone know

(a) why Emacs has both functions, and

(b) if/when their results can actually differ (apart from the obvious
cases like I mentioned)?

TIA,

-- 
Marcin Borkowski
http://mbork.pl