This can be repeated 19 times...we certainly don't want a 20th repetition, since that would drain the opponent to 0 life and end the game prematurely, and that's bad
While there is the downside of not triggering enters and leaves abilities, being able to essentially save a creature you have in a moment of crisis isnt to be underestimated
All of that being said, Bloodletter is also just a good card in general since combat damage also counts as life loss
Each Gnome token can enter attacking a different player, planeswalker, or battle, and they don't need to be the same ones that the non-Gnome creatures are attacking
Not every deck has to follow a tried-and-true strategy though, sometimes you want to do something a little different
To make matters worse for your opponent, its deathtouch ensured it traded efficiently no matter how it was blocked