More powerful alliance gets better loot
4* heroes are the back bone of empires ( see notes )
4*+19 heroes are roughly as powerful as Classic 5* 4.80 heroes.
So 4*+19 heroes let you defeat higher level titans and get much much more loot ( one player on the forum claims 10* titans drown you in 3* ascension items - see notes for math ).
Better titan loot lets you level more 4* 4.70 and 5* 4.80 heroes.
More 4* 4.70 and 5* 4.80 heroes let you use more emblems.
Which let you get more emblems for less energy and less 3*/ 4* ingredients spent.
It is a classic example of the more powerful your alliance is in the game, the more loot your alliance gets.
Since it is easier to get good 4*+19 heroes, this removes the problem with getting good 5* heroes.
F2P
Since most emblems are equally available for F2P and P2P accounts, this reduces the F2P account’s reliance on lucky summons to build up a good roster of 10* titan killing heroes.
Notes
4* Heroes are the backbone of Empries
Some heroes are good, some suck, most are just okay.
RNG decides if you get good 5* Heroes.
You get three times as many 3* ascension items as 4* ascension items.
Legendary training gives you, on average, a 4* hero every ten days.
Gem summons have better odds of getting good 4* heroes ( looking at you Rigard, Wu Kong, Jackal, Hansel, Proteus, Wilbur, etc. ).
The game makes it easier to get good 4* heroes than good 5* heroes.
4* 3.60 heroes are the most powerful heroes in the game with 1*/2* ascension items.
4* 4.70 heroes are generally more powerful than 5* 3.70 heroes and require similar Hero XP to level.
Personally, I have been playing since 2017-Sep and still do not have any green 5* hero, any Splash damage 5* hero, a second 5* healer, and I am drowning in sucky - or okay - blue 5* heroes. One of my two good 5* heroes is a solo hero, his special ability does not help his team.
4* Heroes are the backbone of Empires