The difference is the balance between internal resistance and capacity.
Internal resistance is the difficulty for the charge/electrons (inside the battery) to get out of the battery, and capacity is the amount of charge/electron the battery hold.
My theory (and is probably true) is that for high-performance batteries the leads/sheets inside must be thick to
- allow charge to flow through without overheating and
- decrease resistance, which increase current and voltage for the load.
Of course, if you increase the thickness of the conductors/sheets, you decrease the surface area for charge to cling on to. Thus high performance batteries (e.g., that RC car battery) have a lower density compared to ordinary, medium batteries found in laptops and phones and low power batteries found in, say, wireless mouse or alarm clocks.
But in exchange they have a better discharge curve and perform better under high-load environments.
Which, due to their low internal resistance, is also more dangerous if you accidentally shorted one out as hundreds of amps can flow through.
They are also typically non-protected because the total resistance must be as low as possible for minimum heat and max power (to the RC car motors). Some of which can go as fast as 60Km/h and pop wheelies.
The battery you chose is non-branded -- it probably will do the trick, especially since it have high capacity which means it's less likely to be stressed even the output is relatively high (e.g. 2A), but don't expect it to drive anything more powerful, especially if you use more powerful motors.
But quality batteries are quite difficult to come by, so if you have laptop battery pack with identified "broken" cells you can re-use the cells that are still good, since laptop are power hungry (45W) and the cells must be good enough to meet the performance ratings.
And, obviously, they can also tweak the chemistry slightly to affect characteristics. The famous "LG Chem", for example, is a good "breed" of power cells for Dysons and other stuff, but are somewhat low density compared to some Panasonic stuff.
