What copies of my database, if any, do readable secondaries make bigger?

Suppose that I have an Enterprise Edition database that has completely default settings and nothing but normal rowstore tables. No RCSI, no snapshot isolation and no triggers. Assume nothing that would require [row versioning](https://learn.microsoft.com/en-us/sql/relational-databases/sql-server-transaction-locking-and-row-versioning-guide?view=sql-server-ver16#space-used-in-data-rows) . Clearly, these assumptions mean that I will not be paying the extra 14-bytes-per-row cost of row versioning. However, readable AG secondaries run under SNAPSHOT isolation and SNAPSHOT isolation requires row versioning. So if I put my database in an Availability Group and add a readable secondary, what copies of my database (if any) will start paying the 14-bytes-per-row cost of row versioning? Does this change if I have a non-readable secondary in addition to the readable secondary? What if I fail over and fail back? The relevant documentation, linked earlier, makes no comment on this. I plan to run experiments myself, but AGs are notoriously easy to make mistakes with and I don't want to draw incorrect conclusions.