Hitler amongst many others was 'popular'...Populism is popular, why wouldn't it be, what's not to like?
And you say what's not to like about populism and voting against your own interests?
Populism hijacks the plight of (mainly) poor people and usually adds in a bit of 'it's all johnny/jane foreigners fault'...
A well used tactic all the way through history, simply because the gullible are easily led by the few who stand to make a killing...
Usually financially nowadays, but sometimes literally!