[R] packaged datasets in .csv format

[David Firth]

A couple of questions in connection with using .csv format to include 
data in a package:

First, the background.  The data() function loads data from .csv 
("comma-separated values") files using

   read.table(..., header = TRUE, sep = ";")

But ?read.table says

      ## To write a CSV file for input to Excel one might use
      write.table(x, file = "foo.csv", sep = ",", col.names = NA)
      ## and to read this file back into R one needs
      read.table("file.csv", header = TRUE, sep = ",", row.names=1)

As a result, .csv files created by write.table() as above are not read 
in by data() in the way that might be expected [that is, expected by 
someone who had not read help(data)!]

Two questions, then:
-- is there some compelling reason for  the use of `sep = ";"' in place 
of `sep = ",", row.names=1'?
-- if I want to maintain a dataset in .csv format, for use both in R 
and in other systems such as Excel, SPSS, etc, what is the best way to 
go about it?

Any advice would be much appreciated.

Cheers,
David