It is literally in the subheading on the Barclay's page I linked: "If you don’t qualify for a regular current account, don’t yet have a UK account, or you’re experiencing financial difficulty, this could be the right account for you."
Well yes sorry - the linked account is indeed a "basic" account for people in difficult position, I suppose. But what Barclays calls "regular current account" also doesn't have any overdraft, not unless you applied for one.
Most people have an ordinary account like this one: https://www.barclays.co.uk/current-accounts/bank-account/
However, the general situation for overdrafts seems to have changed since I left the UK — I don't know the details: https://www.theguardian.com/business/2020/jan/28/uk-banks-ov...