We are aware “About Me” page is the only place on your eBay store that sellers are allowed to mention their own URL. If you look around you will find quite a lot of sellers Violet this eBay link Policy like the one below. It is best not to go against eBay policy as this can even cause suspension of your account.
Having link in credible site like eBay is certainly good for SEO of your eCommerce store. However, have you ever thought if this page has brought any traffic to your website and was there any sales from it?
I had a quick glance in one store’s Google Analytics and found out that in last four years the store had one sale with 390 visits which is 0.06 % of the total traffic. I am curious to learn your stat on this.