@AbhishekC1725 please check the below URL. Node level dpage is for meant for whole node level application that covers all the requestors. So as node level data page can't get a specific requestor access as it is not running on a particular requestor level, we explicitly provide access group for it's access. 

http://www.howtopega.info/2018/01/node-level-data-page.html?m=1#:~:text=Reason%3A%20Node%20level%20data%20page,for%20node%20scoped%20data%20page.

Hi @AbhishekC1725: Please check this and this.

Some additional ref:

https://support.pega.com/question/questions-about-node-level-data-pages

https://support.pega.com/question/how-node-level-data-page-behave-multinode-enviornment

Thanks.

Hi @AbhishekC1725,

Thread, Requestor we need not specify any access group. But for the node level, we need to specify the same. Reason: Node level data page acts as a separate requestor that runs in its own execution stack, which is different from any requestor user.

Please go through the below link for your better understanding 

https://support.pega.com/question/why-we-need-access-group-node-level-data-page

Thanks