I think the extent to which scientific names are necessary depends on how you
view the subject matter, or to put it another way, how you approach the hobby.
In any field of knowledge there is a certain amount of technical terminology
required, IF you intend to pursue that interest to more than a superficial
level, and IF you intend to communicate with others who have similarly pursued
it. The woman in the office next to mine is into ice skating, and sometimes
talks about events she has watched or participated in.  Salchow ( I just asked
her how to spell it - I would have put sowkow) means no more to me than
Cypraea does to her.  But for her it is a necessary vocabulary word, without
which she would be unable to easily converse with others who share her
interest at the same level.  This doesn't mean you can't enjoy the thrill of
ice skating without knowing the technical terms - of course you can!  I think
it's the same with shell collecting.  I wouldn't dream of saying that every
shell collector must learn the scientific names - some collectors don't need
them in order to derive pleasure from their shells, in the way they most
enjoy, and I see no reason to be critical of that.  But the fact remains that
IF we wish to pursue the more scientific aspects of the hobby, then we do need
to develop a vocabulary which will enable us to converse with others, and
understand the more technically-oriented publications we read.  Irene
mentioned that she would not refer to a robin as Turdus migratorius in
speaking to her 14 (!!!!!!) grandchildren (gee Irene, I only have 3).  Neither
would I - but serious birders DO use the scientific names, for all the same
reasons as shell collectors, butterfly collectors, and horticulturists.  As
long as one is comfortable with one's approach, there is no reason to force
onesself to learn that which has no immediate practical value.  On the other
hand, if one chooses to, or is gradually drawn toward, a different approach,
the appropriate vocabulary will necessarily come naturally, over time.
Incidentally, "Turdus" translates as "thrush"; "migratorius" obviously as
"migratory".  Therefore the robin's scientific name means "Migratory Thrush".
There is a cowrie named Cypraea turdus - common name - what else?  Thrush
Cowrie!
 
Paul M.