What's the point of using these phrasal verbs? Please explain because I don't get it?

To my ear, "clean" and "clean up" mean pretty much the same thing. Perhaps "up" suggests picking things "up" from the floor or wherever they don't belong, or it might intensify "clean." When it's used figuratively, such as, "The new mayor's going to clean up crime," it suggests a long and complex action.

"Fall" and "fall off" are slightly different. The "off" means that it fell off of something. You can say, "The leaves have fallen," but "The leaves have fallen off" or "...fallen off the trees" is more specific. If person or something standing up "falls," you can add the adverb "down" (if fell down *from itself*, so to speak -- almost a reflexive that's unspoken).

Same with "topple." If you want to say only that a thing topples, that's fine. But if you want to be specfic -- if there's an object over or from which it toppled, you need a preposition: "to topple down from the building" or "to topple off the building" or even "to topple over [adverb] from [preposition] the building."

"To tolerate" and "to put up with" are synonyms. Perhaps they derived from phrases in other languages.

I wouldn't know cool or trendy from a hole in the wall!

This interests me because I'm trying to make sense out of Latin, which often uses prepositions differently from English.

> Is it cool or trendy to use phrasal verbs or what?

It's normal, and has been for over 1000 years!

Phrasal verbs are standard in Germanic languages, and English inherited the use of phrasal verbs from Old English, the Germanic language it descended from. We use them because they're part of age-old idiom, right at the core of how English as a language uses verbs to express old meanings and create new ones.

All phrasal verb variants on verbs give a greater or lesser change of meaning from the basic verb.

Edit: I did answer. If you don't get it, that's your problem. You don't accept that they're normal, or you wouldn't ask whether they're "cool or trendy". English uses phrasal verbs because that's the long-standing way English does it, as opposed to using later Latinate forms.