A low resistance battery, in the usual Li-Ion speak, is one that has a low internal resistance and is capable of outputing higher currents without damage to the internal structure of the battery.
An AW IMR is a low resistance battery. A Trustfire black label is not.
A low resistance Li-Ion cell is preferred for LR attys because LR attys draw more current and can damage typical Li-Ion over time.
While some typical resistance Li-Ion cells can run a LR atomizer without any issues, it does not hurt to use a low resistance cell anyway to save yourself from having to learn about
batteries and math. Plus, a low resistance Li-Ion cell can run a higher resistance atomizer without any problems. So investing a little more in a better battery keeps your options open no matter which way you go and will usually result in a longer lasting battery and a net savings over time.