Under online registration tab of event setting there is a option 'Use a confirmation screen?' to show or hide confirmation page. This option is only available for free events. For paid events the option doesn't show up on screen and if you set to skip via sql or api for the event it still show confirmation page. How can we have this option visible for paid event as well? Are there any drawbacks of not having it?
Yes you are right, the option is only available for free events. I believe some payment processor will need confirmation page(incase of paypal express) hence the option is always hidden for paid events.
You can try installing skip confirmation page extension, this should show the Use a confirmation screen? option for you for paid and free events.