The concrete floor will not be moisture proof and damp issues will occur if another floor is not correctly installed.
You loose your car parking space, which can increase your car insurance premiums, as well as loose valuable storage areas.
The ceiling lining may now be an asbestos sheet, above where you have a bed positioned as any house built prior to 1985 would have asbestos sheeting used for the carport ceiling lining.
I do find a lot of wall moisture issues, mold issues etc in any converted carport wall. This then becomes a possible termite attractive zone, as the cladding is often over carport posts, that have inadequate or preventative pest treatment applied. The wall framework is often set down against the pathway or worse the driveway edge at ground level. This can enable moisture to wick up inside the framework providing the damp timber that attracts termites.