The classies are as safe as, well, classies.

There are always risks.
You can, as a seller, choose who you deal with. You can choose to deal with only people that have X amount of trader ratings if you want. Likewise, you can choose to only deal with people who have X posts and their account is X years old. Or a combo of all the above.
P2P selling is always a gamble unless you take cash only, up front. Which isn't happening on online transactions.
Then you have the problem where someone can do a chargeback on a paypal transaction and you, as a seller, are SOL even if you have proof of delivery. You, as a seller of vaping gear, also run the risk of losing your PP account if paypal finds out. So there's that problem, too.
People will give anecdotal "proof' that they've been using PP to sell their vape gear for years without problems, but that doesn't change the fact that PP reserves the right to shut you down over it. Vape transactions are forbidden in their TOS.
Also, ECF does not allow sellers to use Paypal Friends and Family, which is the solution to buyer fraud, because it is easy for fraud sellers to defraud buyers since buyers since buyers are not protected by paypal if money was exchanged in a Paypal F&F transaction.
But PP F&F is a safer option for the honest seller. Go figure. (What bothers me about that "no F&F" rule is that, as far as I know, ECF allows Bitcoin, yet Bitcoin has no buyer protection either, so to disallow paypal F&F makes no sense - actually Bitcoin is a lot easier to use to defraud buyers than PP F&F is - but I won't go into why that is).
Classies are a gamble no matter where you post them. But I think here on ECF it may be a tad safer seeing how you can more easily deuce who might not be trustworthy than on other venues.