Its still a 1/1 with no other abilities, but itll at least stick around and block a few attacks
Third, it still costs mana and time (or life, in the case of Street Wraith) to use
Now, since the Quicksilvers ability is a new instance each time it copies Vivi, you get a fresh activation
Are they part of a broader artistic trends you are seeing come up
You can do this by attacking with two or more creatures, sure, but more commonly youll do this by just dropping your load of dice on the board through other means or just saying nah and drawing 25 like the Simic player we both know you are
As you cast a spell or activate an ability with one or more Phyrexian mana symbols in its cost, you choose how to pay for each Phyrexian mana symbol at the same time you would choose modes or choose a value for X