A good selling group is not a bad version of a marketplace. It is a different thing that does some of this better, and being honest about which is the only way this comparison is worth reading.
What a group genuinely does better
Trust you already have. Everybody is known to somebody. That is the strongest thing in commerce and no platform manufactures it.
Speed. A photograph and a price, and it is sold. No listing form, no delivery profile.
Nothing to learn. Your buyers are already there, already scrolling.
What a group cannot do
Hold the money. Payment in a group is a transfer between two people on trust, and if the parcel never arrives there is nothing in between to put it right. On Metzee the buyer's money is held until the item reaches them, which is the single structural difference.
Keep a record. A scroll is not a ledger. When it matters — a return, a tax question, what was actually promised — you are searching a chat.
Settle an argument. If a buyer says it arrived broken and a seller says it did not, a group has only the two of them and an audience. A dispute here is opened, answered and decided within 48 hours by somebody who is not either of them.
Reach anyone new. A group is as big as it is. That is its comfort and its ceiling.
The honest answer
If you sell to people who know you, in your own town, a group may be all you need. If you want buyers who have no reason to trust you yet, something has to stand behind the transaction, and that is what a marketplace is for.
Many sellers run both: the group for regulars, Metzee for reach and for anything expensive enough that both sides want protection.
Questions people ask
Can I bring my group here?
Yes, and the usual way is to keep the group and use it to announce your shows.
Is it cheaper to sell in a group?
There is no commission, so yes, on fees alone. What you are paying for here is the held money and the dispute route.
Why not just take the payment directly and save the fee?
Because the protection goes with the payment. A deal moved off the platform has no hold on the money and no route if it goes wrong, for either side.
More: why off-platform deals are risky, compared with selling on Instagram, why we hold the money.