Main drain delete normal when installing new skimmer?

Currently renovating my pool and the contractors decided that it was best to delete the connection to the new skimmer to the main drain because the "cooper piping was corroding". They instead created a hole about a foot under the skimmer to add the sidewall suction.

Is this normal?

I thought it was a little bizarre that they didn't ask if we want to keep the main drain as an option but went ahead and completed the delete.