We hand-picked a few rivals that the Xperia 10 will have to face on the market, and it's not going to be an easy sell, the 10. For example, the Galaxy A7 (2018) offers a more powerful chipset, an extra ultra wide camera, superior display, and vastly longer battery life, at some 30% lower price. It's not ideal, of course, as it charges slowly (over microUSB 2.0, at that), lacks 4K video capture, and its Samsung software may not be to your taste if you're eyeing the Xperia for its vanilla Android.
Vanilla Android is what the Moto G7 will bring you though, and will do it for less cash than the Xperia, again. Even the otherwise not very energy-efficient Moto will outlast the Xperia in actual use, but in the other areas that matter the two are very much tied. Which is where the Moto's price trump card comes in.
The Xiaomi Mi 8 Lite is also more affordable than the Xperia 10, runs on the more powerful Snapdragon 660 while also lasting longer in the process. The Mi's MIUI is diametrically opposed to the Xperia's vanilla Android but we can see how both can have their fans.
The same could be said of the EMUI in the Huawei P smart 2019, but from a more objective standpoint it's got longer battery life than the Xperia, and its Kirin 710 is once again brawnier than the 10's Snapdragon 630. Neither has the best image quality, though the Xperia is perhaps superior, plus it records 4K video, unlike the Huawei. The P smart 2019 is cheaper, though.
Much like the Xperia 10 Plus, the non-Plus isn't a strikingly good value proposition. On the contrary - there's a ton of competing offerings that deliver more for less. Particularly disappointing is the Xperia 10's battery life, and it's not like you're trading that for top performance - in fact, most rivals pack more punch.
If, on the other hand, the tall aspect screen is exactly what you've been waiting for, and you're after a compact midranger, by all means go for it. Ideally, with a carrier subsidy. Or a couple of months down the line, when the 10's price drops by a few 10s.