What tankless actually gives you
Endless hot water at a given flow rate, and the floor space back. Those are the two real benefits, and for households that run showers back to back, the first one matters a great deal.
It does not give you instant hot water at the tap. That is a recirculation question and it is separate.
Where tankless disappoints people
Undersized gas supply. A tankless unit can demand more gas than every other appliance combined, and running it on the existing line is the most common reason a new unit underperforms.
Low-flow fixtures dropping below the activation threshold, which causes the cold-water sandwich effect.
Skipped descaling. Annual service is not optional; performance falls off noticeably without it.
The North Carolina advantage
Groundwater temperature here is mild compared with the upper Midwest or Northeast, so the temperature rise a tankless unit has to achieve is smaller. A correctly sized unit maintains full flow through winter, which is not true everywhere.
The cost comparison, honestly
A tank replacement runs $1,250 to $2,450 installed. A tankless conversion runs $3,200 to $5,400 because of gas, venting and water routing.
Tankless units last longer - often twenty years against ten to thirteen - and use less energy. Over the full lifespan the numbers get close. Over five years they do not.
If you are replacing a failed tank on a normal budget, another tank is not the wrong answer. If you are remodeling, adding a bathroom, or repeatedly running out of hot water, tankless earns its cost.