Same Trip, Two Outputs: Portfolio Metadata vs. Client Deliverable
The short answer
The same trip feeds two different readers. Your portfolio edit wants long-tail keywords and a stock-ready caption; the client deliverable wants a project ID and a clean rights line. Both live in the same IPTC and XMP fields, so you can write them in one pass over one ingest, then export two branches without re-keywording a single frame.
You flew home from the assignment with one card full of frames and two jobs waiting for them. The tourism board that commissioned the shoot wants its deliverable: the frames it paid for, labeled with the project reference, the usage it licensed, and nothing it did not ask for. Your own site, your stock portal, and the book you are slowly assembling want the other edit: the long-tail keywords, the searchable caption, the full copyright line that keeps the image yours.
It is one trip. It becomes two outputs, and the difference between them is almost entirely metadata. The pixels are the same. What you write into the file is not.
Most travel photographers I talk to keyword this twice. They build the client deliverable, deliver it, then come back weeks later and re-tag the same frames for the portfolio because the two jobs felt like two projects. They are not. A good travel photography delivery workflow treats them as one ingest with two export branches, and the split is cleaner than the double-handling makes it look.