R: reading big data files in R
In R many great improvements are typically made by creating new libraries rather than changing the actual functions in base R itself. datatable, read_csv in readr, tibbles, etc are very good examples.
read.csv vs fread as answered by Matt Dowle himself
read.csv coerces strings as factors by default which is not done by read_csv and fread. So if that is what you need, read.csv will work well. Now answering your question,there is no disadvantage using the fast readers to read small files apart from a small speedup that you might get.