The advantage is you can apply the past 100 years of organic chemistry development to specifically build whatever molecule you want without having to deal with separating out the desired hydrocarbon molecules from the complex glop called 'crude oil'. This is essentially what's going on in modern natural-gas-fed petrochemical facilities (although natural gas is often itself contaminated with sulfur and mercury species, like H2S / H2Hg etc.).

The disadvantage is that there's a high energy cost involved in stripping oxygen off carbon dioxide and replacing it with hydrogen (it is storing energy in C-H and C-C bonds). As the cheap easy-to-extract oil is mostly gone at this point, however, these costs are approaching parity.

The real necessary use cases of hydrocarbon fuels are for rockets and jet airplanes, as battery energy density is just too low. Long-distance oceanic shipping is another area where hydrocarbon fuels might be necessary, although there are some other options (wind/solar/iron redox).