Hello! Thank you for your question! We have talked about this as a mod team and have adjusted our physical merch application to now accept mockups of merch designs as samples with at least one sample being a manufactured piece being highly recommended. As this is a merch project, we want to make sure that our contributors are familiar with the requirements and specifics that come with making merch, which is why we are requiring merch related samples. Your portfolio can contain non-merch samples however.