JavaCard OS

I saw a topic talking about the card status INITIALIZED and SECURED. I have some doubts about the difference between OP_READY and SECURED. I have already read GP2.1.1, but it's a little hard for me to understand.

I really want to know what's the primary difference between the two status.
Compared with OP_READY, what capability does the card lose in status of SECURED?

p.s. I can upload the applet, install the applet and delete it successfully in both two status. It seems that there is no difference between them.
I will be very grateful if somebody help me clarify these doubts!

In my opinion, OP_READY is the very initial state of a card. In this state the card is ready to be personalized (e.g. add SSD, add keys to the security domain). Moreover, any pre-loaded executable load files will be registered in the GP registry (i.e. visible if you list applications/executable load files) and the ISD has an initial key set for card management.

SECURED is the state the card should be in when delivered to an end-user. In this state, security domains for production use should have been setup (i.e. you installed any required SSDs, set up all the necessary management keys, etc). Any of the pre-loaded executable load files that where not used (i.e. not installed) will typically no longer be visible in this state. You will still be able to load and install applets in this state. And you should still be able to change keys in this state.