The problem is businesses may take it as a signal that the EU is against foreign businesses rather than against monopolistic practices, in which case the thing being deterred is doing business in the EU rather than monopolistic practices. To show otherwise they would have to levy equally large fines against local businesses engaged in the same sort of practices, which they haven't and likely won't.

If they really wanted to signal discouragement of monopolistic behavior rather than a cash grab they would be ordering specific conduct rather than excessive fines. For example, if the issue is that they promoted Google Chrome in an unacceptable way, prohibit them from distributing Google Chrome in the EU for five years. And then do the same thing to Microsoft just to be even-handed, because they're still bundling their browser with Windows. And likewise with Apple and Safari.

Let everyone use Firefox for five years and see how much browser bundling happens after that.