They're only efficient and low-cabon if you compare them to coal, not if you use basic sanity that building any kind of new fossil infrastructure is madness.
Even the low carbon of fracking is questionable given methane leaks.
The only viable kind of gas is biogas which you have to sequester anyway. Other kinds speed up the catastrophe. There cleaner than some coal and oil but that's about it. They're not even close compared to nuclear or renewables.
Why do you need gas? Can't use the electric vehicle or appliance? If you need trace gases for manufacturing, you can sequester them instead.
No, you can create Methane out of thin air with electricity and store that in the existing infrastructure for strategic gas reserves. https://en.wikipedia.org/wiki/Power-to-gas
It's a very convenient way to store large amounts of energy for dark, windstill winters. If you then have a decent number of gas plants you can turn it into electricity to run the heat pumps in your homes.