do i really need a hotel reservation and book flights ticket when applying for chinese visa?

I'm afraid so. You need to submit the round-trip air ticket. If you are afraid of being refused for the visa, you'd better buy refundable tickets.
For hotel reservation, you can provide the invitation letter from china side as a replacement.
FYI: https://www.travelchinaguide.com/embassy/visa-application-philippines.htm