The Chronocle Fiend was aware of its weaknesses. It had yet to mature into a horror that Deities of Suzamete's calibre would truly be wary of. The fact that she had sent a bunch of mortals to fight it showed just how low she regarded this particular Fiend.
The reason she wasn't too concerned with it was because she knew that unlike Impermanence Fiends, Chronocle Fiends needed to learn efficiency to survive. Without that skill, they would simply use themselves up without bringing anything of consequence about.
The hesitation the Fiend had earlier was based on its knowledge that it was terrible at efficiently applying its time-abilities, especially on stronger mortal beings. It couldn't even isolate individuals with its attacks yet.