This font looks very fun and swoopy in the preview, but on opening the page, the actual font is very different. Why is that?

What's software that you use? The styled characters are available as alternative characters. Please check this screenshot: https://ibb.co/j3ZCY7x

Thank you

Why is the yasmen font looks as curly and fancy but when you use it it's just plain? not a bit like the showcase

Each letter has some variations. You should open the glyphs to see all the characters.