When you are referring to internal linking as helping you, any shop on Etsy should only be concerned with the internal link of their own site domain. Etsy.com is a primary domain, each of our shops operate off of a subdomain. When you are internally linking throughout Etsy.com itself, you are helping Etsy. PERIOD.
Your subdomain shop such as (shopname).etsy.com is its own subdomain and your internal linkings would be things between your about, shop pages and listing product pages, etc. This is why I tell people to add links to their categories or other products internally in their own shop if you want to drive it up within the description section of your listings.
Etsy.com has a very high authority on Google well over the 90's. However, your own subdomain for your shop beneifts little from this in the longterm. Some shops I have none well over 5 years only find an authority level of possibly over 20 after a lot of hard work and sales. A treasury would be considered a newly created page with Google and drive no form of authority or Google juice outside of helping only Etsy as a whole. If you think linking yourself on a 0 page authority site with 12 other product links is going to boost your long term results, you are being misled. Sure you would see a short term boost of views because you are being promoted, but chances of conversion in that is very low. It is better to build up your own product pages and list more in your shop creating your own added internal pages and promote on social media and other realms from high ranking sites to gain outbound links and more Google love in the long term.
BTW: I would like to add, there is a reason why site such as Etsy do not allow clickable links to outside domains. Since they are a high ranking site, they would be giving away their site juice to other low ranking sites on Google. Instead they only allow internal clickable links between their own subdomains to keep it all to themselves. In the SEO world, this is actually pretty frowned upon and considered to be psuedo unethical.