Despite misgivings, another 33% say they plan to buy something via a voice assistant.

Voice-controlled assistants, such as Amazon Echo devices or Google Home, are becoming an important online sales channel, even if they also create some concern among shoppers, according to a survey from marketing and communications firm Walker Sands Communications.

The Walker Sands survey of 1,622 U.S. consumers found almost one in five consumers (19%) have made a purchase using an Amazon Echo or other voice-controlled device in the past year, and another 33% plan to do so in the next year. In addition, 24% of surveyed consumers said they already own a voice-controlled device and another 20% said they plan to purchase one in the next 12 months.

That means voice-controlled devices still have a long way to go to match the penetration of smartphones and tablets. By smaller margins, voice-operated devices continue to be less popular than streaming content via televisions and home automation via the internet of things, which allows for remote operation of lights, thermostats and security systems from internet-connected devices.

Consumer apprehension also may slow the growth of voice-controlled devices as an e-commerce channel. Those surveyed by Walker Sands expressed a variety of concerns about using voice-controlled devices to buy things online, such as security (38% of respondents), followed by privacy (33%) and lack of visuals (31%).