The push fit coils help reduce mess when changing and are much easier to remove and replace.
On the Aspire Tigon tank, coil replacement is just a case of unscrewing the base hardware, pulling out the old coil and replacing with a new one. Then screwing the base hardware back on again. Note that the Tigon tank can still hold e-liquid when changing the coil, this is because the wicking holes in the tank are covered by a spring loaded sleeve that will slide shut sealing the holes when the coil is removed.
Remember, before using a coil for the first time to let it stand for 5 minutes after filling with e-liquid to saturate the coil and avoid dry hit and damage to the coil.