Most of this site argues that online groups work, because the evidence supports it and because for a great many people the alternative to a remote group is no group.
That isn’t the same as saying the format never matters.
The clear case
Social anxiety. The one place where the room has a genuine edge.
On video you can angle away, watch your own face, control your framing, and leave your camera ambiguous — and all of those are the safety behaviours the treatment exists to remove. An in-person group takes them away by construction.
Online groups for social anxiety still work well, so this is a preference rather than a rule. If one is available locally, it’s worth choosing. More here.
The softer cases
Long-term process groups. The material is what happens between people, and video loses posture, position, and who turns toward whom. It’s a smaller loss than expected and it’s a real one.
No private space. If you genuinely can’t take a call without being overheard, an in-person group solves a problem that no amount of technique will. This is the commonest practical reason.
Screen exhaustion. If your working day is already eight hours of video calls, a ninth is a real barrier to attending at all.
Higher acuity. Where someone needs closer monitoring, a room is easier to hold.
The case against waiting
Which is usually stronger, and worth stating plainly.
Groups need six to ten people who want the same thing at the same hour. Locally, for anything specific — a condition, a population, a language, a particular kind of loss — that frequently does not exist and won’t.
So holding out for an in-person version of a specific group is often holding out for something that isn’t coming, while an online one is available now. This is why the good specialist groups are disproportionately remote.
And attendance isn’t a minor consideration. A weekly commitment with travel attached has meaningfully higher dropout, and a group you complete beats a better-formatted one you leave in month three.
Hybrid groups
Some groups run with people in a room and others on a screen. Handled well this is a reasonable accommodation for someone who occasionally can’t travel.
Handled badly it produces two tiers — the people in the room have a conversation and the people on the screen watch it. If you’re considering one, ask specifically how they stop that happening. A leader without an answer hasn’t solved it.