That is a bit my comment. A creature is defined as its movements (attack, counterattack and swap) and by 6 additional features:
The first two are increasing as the level is increased while the other four are independent of the levels.
The creators of the creatures have tried that the creatures are balanced and I think they have done well with some faults (for example too much difference between the unique, some Tyrant and other Apex 3, error that is partially solved in this version). For example, if they give great speed or immunity to a creature they usually take away health and damage to compensate. Creatures with great damage usually have low speed and relatively little health, etc.
If Boosting affects health or damage, what we are doing in a covert way is to level up. A level 21 creature with a health boosting of 5% and a damage boosting of 5% is exactly the same as the same level 22 creature with the only difference that in case of fighting against each other, the second will take priority. I do not like the idea because those two small boosting are almost equivalent to the hard task of increasing the level of the creature, but I think that the affectations to the game are limited because each increase of 5% of the two variables equals the creature with the one of a higher level.
If boosting affects speed, we are simply creating a different creature and breaking the design made by the creators of the creature. A 5% increase in this variable can mean the increase of many levels in the game (A TREX level 15 will win, critics apart, to a TREX of 22) and will cause some creatures to be left without the counter that the designers had created for they. Something similar would happen if someone could buy the immunity of a creature or the critical chance, for example.
Of course, it’s just an opinion.