As far as I remember, Sweden did deliver to the US certain wanted people practically without a court procedure (or with less than it's certain it would be neede

As far as I remember, Sweden did deliver to the US certain wanted people practically without a court procedure (or with less than it's certain it would be needed in the UK). It's not that Sweden or the UK would not deliver somebody to the US, it's that in the UK the procedure is more complex. Apparently, the US would have needed to fulfill less formalities to get him from Sweden, and that is what Assange worried about. But as he spent enough time in the embassy, that advantage of Sweden became irrelevant.