The question was actually subtly different;
“Brothers, what shall we do?”
and the "saved" part comes later:
40With many other words he warned them; and he pleaded with them, “Save yourselves from this corrupt generation.”
So one could ask why, if
Acts 2:38 was sufficient, have any more words?
(ignoring for now that both
repent and
be baptized surely have different meanings for you now; demonstrably so)
This presents the truly bloodless salvation; one without suffering. How far from some Prosperity Gospel can one "converted" in this fashion be?