1) Not Private enough
2) information can be tracked by the company that offers the free service
3) information is not always deleted
4) information is typically sold to 3rd party ad companies.
5) when there free; you basically get what you pay for. Almost as bad as the spam add frees sites.

Tell us your bad experience with 3rd party Form Apps.

Always like option for alternate screening but screen is very import for safe hobbying.