Well it depends... there is no weight and balance licence required in Europe, I don’t know about the rest of the world. It is possible that an agent starts on a Monday with no aviation experience and is producing a load sheet on Friday still with no aviation experience.
I know for sure BA requires licenced people to produce loadsheets, be it locally or CLC. You get the basic training (both manual and DCS) and a resfresher course every three years. If you fail the tests, no loadsheet licence. You need a score of at least 90pct. In the days BA caried RRY, a mistake with this costs you 10 pts, so even a missing comma will cost you your license.
I have been in CLC several years, and I can assure you that for some stations it's a good decision to have CLC make up the loading instruction/loadsheet.
Naturally it helps when TRC (turn round co-ordinator) has (good) knowledge about weight and balance, in case of problems such as overload, out of trim, ....