Why do companies register only as recipients?

Because Peppol only needs to register recipients — senders operate via their Access Point.

Within Peppol, only recipients are registered on the network. Sending can be done via any certified Access Point without additional registration. This keeps the system simpler and more reliable. This also means you can use different access points for sending. Very useful if you have, for example, a webshop where invoices are created automatically but also create invoices manually with other software.