what are the pros and cons for getting data from third-party through REST outbound call??

[Manikantahere]

When an end user requested a catalog item it triggers multiple sequential/parallel approvals to get approvals we are using power automate as we are sending all the details to power automate. 

once upon approver response  power automate can take same response and can update in SN approver table with OOB options.

but instead the client decided to go we need to fetch power automate data frequently to update approver responses back in SN.?  What are the disadvantages of it?

1) This is not going to be realistic as we are triggering schedule jobs either twice or thrice per a day (request needs to wait until the response comes in next schedule)

2) I should not depend on flow as I need to write schedule job outside the catalog item flow (Note: I can write the SJob inside the flow but this going to happen for each request and more nd more calls leads to performance issues)

any important points I missed other than the above? 

Note: Considering no cost for each outbound call from SN I haven't added any cost issue here. 

[John Dahl]

Since the approvals are for activities in ServiceNow, I would recommend having users act on the approvals directly in ServiceNow.

Having said that, there is no reason you cannot have REST API calls to update the status of the approval records, but you will not be able to depend on the integrity of the approvals. Identities of the users approving records will not be reliable for audits in ServiceNow. The fact that you're using Power Automate to automate the approvals suggests that the approvals are a "rubber stamp" of sorts and will not provide the intended value. If the approvals are not necessary, consider removing them altogether. It's better to not have any data than to have fraudulent data.