This is likely true, but there's more to it. The iPhone SE's $399 base price seems cheap because iPhones in general are so absurdly expensive. You can shell out $949 on an iPhone 6s Plus if you aim for the 128 GB model. That's almost a thousand dollars — for a smartphone that will be out-of-date in little more than a year!
Now, at this point someone could reasonably argue that the iPhone SE is not a budget phone — but it is a budget premium phone. After all, its internals are largely identical to the 6s.
This is also not true! Our recent affordable phones roundup includes three premium-quality Android devices that compete with the SE on specs but come in under $350. And none of them limit you to 16 GB of storage.
The iPhone SE is great at exactly one thing: Being a pricey, well-made device for iPhone lovers with smaller hands. If you're buying on a budget, you should probably look elsewhere.