Apart from it meaning that the honest sellers offer a good product, at a good price with a good level of service. All of the best sellers have that
Silver and gold coins are far less likely to be re-engraved, although unfortunately in the last 5 - 10 years, even denarii and aurei are being tooled. So far, I haven't seen any obviously tooled denarii from Lanz but I would be cautious about any coins from them, and if you're interested in one, you might want to privately consult with selected collectors on this site.
Look at this notorious seller with 100% feedback. 100% eBay feedback means nothing for ancient coins. https://www.ebay.com/sch/m.html?item=352222559554&_ssn=highrating_lowprice&_sop=16 Yes, there are honest sellers with good stuff that have 100% feedback. But there are scam artists selling at 10x the price or just selling fakes that have 100% feedback.
Glass half full or glass half empty ? 90+% of my purchases are mad on Ebay and the feedback always counts for a great deal.
I sell on ebay everything guaranteed with out time limit mostly fixed price but I usually have some auctions going as well. seller id xago I will be posting a quite a few of sestertius for auction the next few weeks also I usually dont talk about my ebay store on here because I never can figure the rules on these sites I dont even post on Forum anymore although I enjoyed helping people identify ancient Greek coins from time to time in the past. there is a guy from Germany who is always on that site and talks down to newcomers and seems like a jerk, I dont like it for that but numismatically speaking it has a wealth of information