tank dismantle and glass cutting

[loveless]

I am looking into building my own sump atm. I talked to one glazier who said that the edges have to be polished. Am I being misinformed? He said that the polishing process is the expensive part, as it get done by linear inch.

Oh and btw the glass is 3/8 inch thick, his reason for the polishing in the first place as "its too thick to break cleanly"

So my question
Is polishing necessary?