Emulation is almost always slower and eats more battery.
FTFY. There have been some cases where emulation actually outperforms native execution, though these might be, "the exceptions that prove the rule." For example, in the early days of World of Warcraft, it actually ran better on WINE on Linux than natively on Windows.
This article seems to conflate "emulation" and "translation layer". I don't think there is anything that confirms "Prism emulates an x86 CPU", only that it allows for running x86 code on ARM. This does not inherently require emulation as demonstrated by Rosetta 2, which is a translation layer.