Las Vegas: Tech giants Amazon and Google are waging a war with voice-operated Digital Assistants, and the venue of their current battle is CES in Las Vegas.

While the CES show is about latest gadgets including drones and robots, these two companies are grabbing every possible opportunity at the venue to promote their respective Voice-Operated Digital Assistants. For instance, top executives of Google and Amazon are turning-up at media conferences of other electronic goods manufacturers such as Panasonic, LG and Toyota. They are also using traditional ad methods such as billboards, pamphlets and displays on public transport.

Google has plastered digital billboards and the Las Vegas Monorail with the “Hey Google” wake-up command. It’s announced a range of new gadgets featuring its assistant on everything from smart displays to pressure cookers. And it’s sent out the clowns — a jumpsuit-wearing army of advertising associates wearing brightly-colored Converse sneakers and hovering around partner firms’ booths to explain how Google’s technology works.

Amazon, which grabbed an early lead in this market, opted for a more subtle approach. Instead of an advertising blitz, its Alexa digital assistant has merely been popping up regularly in “smart” products across the convention — everything from mirrors and toilets to headphones and car dashboards.

The two companies — and to a lesser extent, Apple, with Siri, and Microsoft, with Cortana — are waging a fierce struggle to establish their assistants as de facto standards for a new generation of voice-controlled devices. It’s similar in some respects to the decade-old battle between the iPhone and Google’s Android system in smartphones, or to the much older fight between Apple’s Mac computers and Microsoft’s Windows PCs.

Both companies see the competition in existential terms. Getting shut out of voice devices could imperil Google’s lucrative digital-advertising business, the source of its financial strength. Amazon, meanwhile, wants to ensure that its customers can directly access its “everything store” in contrast to now, when they mostly shop via devices and software systems controlled by Amazon’s rivals.

For consumers, meanwhile, the spread of these assistants offers new convenience in the form of an ever-present digital concierge. But there could also be some uneasiness about revealing even more about their habits, preferences and routines to distant computers that are always listening for their commands.