The entire invasion of Ukraine looks childish from where I sit. That hasn't stopped them.
> Maybe you think the symbolism is important
It is important in that verbal threats do not carry much weight when so many other threats have already been wagered. For example Putin has already threatened to attack Finland if the join NATO. Sometimes you need a little more than words to get your message across.
> So you think they had to demonstrate they know how to blow up a pipe? Like Western intelligence officials didn't know that?
The intelligence knows for sure. But imagine the effect such action has if it happened that the pictures of gas bubbling up the Baltic sea were shown on TV in every news program for a week.
Maybe you think the symbolism is important, but on the other hand, people might also just think it looks childish...