Where I work, the technical architect is mostly there to get in the developers' ways and tell them when they're using obsolete/vulnerable libraries. Then quarterly they put together a PowerPoint presentation to show which applications are red, yellow, and green based on the above. Now and then the TA will butt into a big project's kickoff to make sure they can bill hours to the project. Then the TA goes into hiding until the next quarter or big project kickoff. I still don't know the TA's name, but they don't get in my particular way, and that's important.

Edit: clarification