Why does Turbotax-online not request the RRSP receipts as attachments, which are wanted on the hard copy return Turbotax generated? See box 20800 on the hard copy.

If you are filing your return using NETFILE, then copies of slips are not sent and you are only required to keep your copy just in case the CRA asks for it. If you are mailing your return, you can add a copy yourself in with the printouts.