Since HDR10 is a free standard, it is more widely available on a range of displays, including TVs, PC monitors, and even smartphone displays. The display manufacturer does not need to pay an extra cost to use the standard and that is why displays with HDR10 are not exuberantly expensive.
On the other hand, Dolby Vision is a proprietary standard. While manufacturers use it to boast about the quality of the display, it usually implies that consumers will also have to pay an extra price for the better picture quality.
The decision about whether to limit yourself to a display that only supports HDR10 or go all-in and buy a device that sports a Dolby Vision-supported display is purely based on your inclination to spend more for better picture quality. If you want better picture quality than an old TV or monitor you are replacing then HDR10 will be adequate for your needs. However, if you need the best possible HDR treatment for all your content, you must go for a device that supports Dolby Vision.
At present, most video disc formats including Blu-ray support both HDR10 and Dolby Vision. At the same time, popular video streaming services such as Netflix (only with the 4K plan), Hulu, Apple TV, and Amazon Prime Video also support both standards on bigger displays but might not support Dolby Vision on smartphones even if the display on the phone is rated for Dolby Vision.