I think the group was definitely more beneficial during pre-Covid times as they organised conferences. But, now, much seems to be in abeyance. Although, that said, they are now instituting an Old English reading group via zoom to be held via participating institutions. To quote an excerpt from a recent mail:
"This would be a collaborative set of sessions that would take place each month and would be hosted by a different intuition each time. At present, we recognise that it has been difficult to meet and discuss our field, especially with those who are outside of our own university communities.
We intend for the host intuition to choose 15 - 25 lines or so of Old English verse to present and discuss matters of language, themes, imagery, history, or any other interesting detail about the text. These sessions will be open to all members via Zoom regardless of Old English proficiency. This will be a great opportunity to meet members, old and new! "
I don't know whether I would term the gesithas as an 'institution' in the conventional sense, but I suppose there could be an opportunity to participate if anyone wanted to. I am not advanced enough yet in Old English so I will not try. Perhaps, you can just sign in and watch/listen.
Lastly, I suppose the other benefit of membership is, I guess, the satisfaction of contributing some money to the worthy cause of promoting Old English learning. Not many organisations do that!
Sæbbi