I've changed the subject of the OP▸ to make it clearer what this is about.
Thanks, Red Squirrel. It can be a challenge to differentiate between the text to use for the title and the question in a poll - something I've got very used to doing over the years, but it's all too easy to make an unclear mixture.
On topic now ...
Electrification onwards from Cardiff to Swansea is very much a part of Network Rail's long term, green / carbon zero agenda, and I would be very surprised to find a vote of members here to come up with a "don't do it" outcome. But then the (real) purpose of a survey/poll/consultation is to find out - either to check what you think you know or to inform or even to surprise.
Carrying on from Cardiff - at least - to Swansea makes sense. Not only for the London expresses, but also for the Swan Line local trains which have been very much in the diesel doldrums. Passenger numbers at Llanshamlet, Skewen, Briton Ferry and Baglan look somewhat low to me; personal experience of using Llanshamlet suggests there might be potential for green growth there with a good local service.
Perhaps there is logic in including overheads up to Maesteg too? Or running that service with 769s, electric as far as Bridgend?
In writing the above, I am not answering "should Cardiff to Swansea be electrified
next?" - I look at Chippenham to Bristol Temple Meads, and Didcot to Oxford as top candiates, with Bristol Temple Meads to Bromsgrove and Basingstoke to Reading as also in my thoughts for the most immediate/first candidates in a rolling program. I am not addressing the question "should we upgrade the line while we are at it?" either.