Is it safe to not catch exceptions when using realm.write

MongoDB Atlas App Services & Realm
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1

I was curious how the code for @ObservedResults handled exceptions when writing and found the following code by clicking “Jump to definition”:

private func write<Value>(_ value: Value, _ block: (Value) -> Void) where Value: ThreadConfined {
    let thawed = value.realm == nil ? value : value.thaw() ?? value
    if let realm = thawed.realm, !realm.isInWriteTransaction {
        try! realm.write {
            block(thawed)
        }
    } else {
        block(thawed)
    }
}

Is it safe to use try! realm.write?

Throws
An NSError if the transaction could not be completed successfully. If block throws, the function throws the propagated ErrorType instead.

What would be an example of a transaction that couldn’t complete (without the block throwing an error)? (Is it simply because of an error while writing to a file)