Why weighted keys?

[Rayancaleb]

Hi,

I want to learn keyboard to do singing practice on it and learn contemporary music. I can't afford expensive keyboards because
I am not sure if I will understand the concepts or develop hand independence or get bored.
so I wanna spend 150$ for new or used one and will play it for a while then I will buy keyboard worth 600 to 700$. What keyboard should I buy which has 76 keys and good action? I'm never going to buy or play real acoustic piano so do I need to buy weighted keys? is playing semi weighted keyboard a good practice?

Any idea?

Please help.
Thanks!

I didn't find the right solution from the Internet.