This is anecdotal, because it's only my experience from being a long time eBay user (buying and selling).
1 Buying on ebay is nice and safe because eBay protects the buyer and will almost always rule in the buyers favour.
2. Selling on eBay is fraught with problems: The Seller is not protected from scams at all. It's easy for a buyer to buy something, and they can flag to eBay that their account was compromised. Because eBay own PayPal they then just yank back the payment until the issue is resolved, and there's nothing a Seller can do about it. See point #1
3. If you are just having a clear-out and want 'some money' for old stuff you no longer want, then yeah it's still worth putting stuff on eBay. You may not get top-dollar for what you sell but at least stuff doesn't end up in landfill.
4. Trying to sell on eBay as a new business is a complete no-no these days. The big powersellers are so entrenched that for most product lines they dominate the search results. eBay now lets you 'boost' your items for an extra fee, which is basically a scam to paper over their broken ranking systems.
5. If you are a new 'business' seller, you are limited to a set number of items up for auction at any one time, which severely limits your ability to get exposure in listings. This is a crazy policy. It is like buying shop premises in a mall, but only being allowed to stock up one shelf inside the shop for 6 months. It's just not a viable start-up situation.
6. If you want to sell as a business, doing that via Amazon is a much better bet these days. Depending on how much you want to pay you can either just list your item and manage everything else yourself, or send a palette of your stock to Amazon and let them deal with everything for you ('fullfilled by Amazon'). tbh, I've not doing this in practice yet, as my current stock doesn't qualify, but it certainly seems more new-business friendly than eBay.