Since you asked the question "why would you buy anything else?", I'll give you the answer:
1. Poor cameras - for the price the cameras are average. The ultra wide is especially poor and lacks auto focus. The normal camera is just OK in good lighting like ALL other phones at this price. The capture and processing of photos takes a long time for some reason and starting a video recording starts with jittering for a second. In other words, in this class the camera is average to poor.
2. The 7200 processor is average for the class in the way the SD 695 is the average for the class, but Poco notably offers MUCH better CPU's at this price, so there are better CPU's available.
3. Average display - according to various reviews I've seen the display is ok, but not the best in class and it doesn't go especially bright, even in sunlight. The competition generally beats it.
4. Accessories - many phones in this class come with chargers, cables and a case in the box. This doesn't. You can only get the accessories from Nothing online, and pay the postage and import duties as well. Whereas at least with Samsung in all countries you will find many shops with Samsung cases, chargers etc with ease. And the other makes typically are well represented on Aliexpress so you could order from there if you cannot find locally.
5. Repairs - This is a big one if comparing to Samsung. For example the A35 costs the same as the 2a yet Samsung has local repair centres in every country and most offer 1 hour walk in service for common items like screens and batteries. The other makes generally don't have this but 3rd party repairers typically will have parts for popular phones like Xiaomi. Whereas with the Nothing 2a you have to courier the phone to Nothing and wait 3 - 6 weeks (!!) [This is what their support told me via email] to get your phone back. And if it was your fault or maybe the phone is 2 years old and you just want a new battery, you will pay the courier costs....
tbh if you can, buy Samsung because they have the best OS upgrade policsy, One UI 6, the best repair options, and easily accessible accessories.
Note: I live in Europe (Cyprus) and this is the situation.