I am sure the new iPhone SE has more advanced everything but if you're just using it for text messages, occasional photo and Whatsapp you'll hardly notice any difference.
I am currently using the original iPhone SE and for my purposes it works just fine. I use it for texting, Google Maps, checking stock prices, occasional photo/movie, email, WhatsApp, bank apps, NYTimes app, Apple Pay. I had the battery replaced last year and plan to use it for the next 3 years or until Apple adds a compelling new feature to the iPhone (which they haven't for several years). I dislike the newer iPhones because they are too big to be comfortable in my jeans pocket.
I am sure the new iPhone SE has more advanced everything but if you're just using it for text messages, occasional photo and Whatsapp you'll hardly notice any difference.