Why do we use syn match instead of syn keyword?

[petdance]

In vim 7.0, the keyword lines in syntax/perl.vim look like so:

syn keyword perlStatementScalar chomp chop chr crypt index lc lcfirst length ord pack reverse rindex sprintf substr uc ucfirst

In 7.3 and above they are:

syn match perlStatementScalar "\<\%(chom\=p\|chr\|crypt\|r\=index\|lc\%(first\)\=\|length\|ord\|pack\|sprintf\|substr\|uc\%(first\)\=\)\>"

Why? Is that an improvement of some kind? My gut feel is that doing matches rather than letting vim do its own determination of what is a keyword would be slower.

[petdance]

From freenode #perl:

donri: match is slower but more powerful, and keywords can prevent other syntax rules to match

donri: for example if you have syn keyword import, you then can't have a syn match /import .../