Can I open a trading account without opening a demat account?

No — at Rupeezy, your demat and trading account are opened together as a single combined account. There's no option to open a trading account on its own without a linked demat account.

Why are they opened together?

Your demat account is where delivered shares are held, while your trading account is used to place orders — the two work together for equity trading, so Rupeezy's account opening process sets both up in one application.