So yes, it doesn't hurt. In fact, it quite clearly helps a ton.
Does that make them pound for pound competitive with one another? No of course not. But consumers are not necessarily buying one or the other on a price basis. Alexa got there earlier. Google has to do something to overcome that hurdle.. being practically free or getting stuffed into something else for free is a successful way to overcome.
Now imagine coming into this arena with none of those integrations. Your system can answer some questions about the weather. It can tell you that your Imap mail account has 3 new messages. Everything else, you've got to do the engineering work yourself to integrate, while Google and Amazon just publish APIs.
I think you could argue Walmart was primarily competing with mom and pop stores a decade ago (though really other large supermarkets at that point), but they are most certainly competing with amazon today.
People would suddenly start to care if the entity enjoys a large enough market share to make them a monopoly.