ZSK > It’s more trying to fit in with the outside culture than anything else.
Sephardim are very much keen on blending with the culture. So, in Arab countries, they dressed like Arabs. Now, when they decided they belong to the charedim, they started dressing like them. It is somewhat ironic – as the charedi garb is the statement of sticking out (after Poles stopped wearing that style), so Sephardim are wearing same but with a totally opposite kavanah: to blend in.