I am Russian but not linguist. I am going to tell how I understand this but I do not know any language theory behind this.
In your example you can use
как будто interchangeably. I think nowadays they more likely say
как будто in this case.
Yes the word
как будто is used to qualify an immediately following word or even a sentence.
If they say
эту яму специально кто-то вырыл this might sound like accusation which in this case is obviously wrong. If they add
как будто they soften the accusation and say that this seems like it was done intentionally but we know that it was not.
Let's look at couple examples.
I say to my friend:
Ты как будто хочешь меня обидеть.
This means that I expect and hope that they have no intention to offend me but they behave like they do, they make me feel they are offending me. The translation might be:
You seem to want to offend me.
Как будто мне заняться нечем!
It might be translated:
As if I have nothing to do!
In this example
Как будто effects the meaning of the next sentence
мне заняться нечем. It changes the meaning to the contrary, as if I say that I have a lot to do now, but also adds some emotions and irony to the statement.
I think I can remember the time when the expression
как будто become popular as a filter word. People tend to use to fill in the pause or to sound modern and cool.
I think the old school version for the last example might be
Мне больше заняться нечем!