This card's name becomes "Amazoness Tiger" while on the field or in the GY. If an "Amazoness" monster is Normal or Special Summoned to your field while this card is in your hand or GY: You can Special Summon this card. You can only use this effect of "Amazoness Baby Tiger" once per turn. Gains 100 ATK for each "Amazoness" card in your GY.
Since Amazoness Baby Tiger can be easily summoned to the field, it can be used as a monster removal card by using Heirloom or Onslaught. Both of these cards makes it so that when you attack with your Amazoness monster, your opponent's monster will get destroyed (banished if with Onslaught). Use Tea's Holy Guard(skill) so that you won't take any battle damage when you attack with Baby Tiger.
If you have a face up Onslaught, use your Baby Tiger to banish your opponent's monster, then activate Onslaught so you can special summon an Amazoness monster from your hand, which will let you special summon Baby Tiger again.
Destroying your Onslaught lets you special summon an Amazoness monster from the grave, which lets you special summon Baby Tiger. This can be good if you have another face up Onslaught to protect yourself.
Use special summoning cards so that you can keep reviving Baby Tiger to be used for Onslaught. There's also Amazoness Willpower, but it's a more restrictive version than Powerful Rebirth. Might be more useful in the future when higher level Amazoness monsters are released.
To make more active plays rather than being defensive, you can use these cards so that you can attack into your opponent without taking any battle damage. This makes it so that you can use any skill instead of having to use Tea's Holy Guard.