Just for clarification - this is not about fme workspace parameters, rather about SQL named parameters.
Named parameters provides better security against SQL injection, improved query plan caching, ensures proper type handling among other things. Another advantage is that it makes it easier to just copy/paste the sql-code from a sql editor (like ADS, Dbeaver etc) where one would be provided with prompts to fill in the parameters.
It would be amazing if one just name a sql paramter the same as an attribute in the feature, and it would be picked up that way… !