You'll have no problems getting English apps; it's just that your phone may not come pre-loaded with specifically English ones.
The primary reason to not get a smartphone is cost. You can get a cheap "dumb" phone on a bare bones plan and spend less than 20,000 a month easily, especially if you don't use much airtime. If you really don't intend on using any of the features of a smartphone, this is a pretty significant savings.
Smartphones are awesome though. I can check bus routes and how far away buses are from everywhere, so I know when I need to leave my apartment or school to catch the one bus I want: no more waiting 10 minutes at a stop. I can bring up a street map from anywhere so I'm never lost. I can look up what restaurants, bars and coffee shops are nearby to wherever I am. I have email everywhere, internet everywhere, a bunch of my music and a bunch of my movies everywhere. I use my smartphone all the time, every day, in ways I never really expected when I got it.
It is expensive though. I pay somewhere around 80,000-90,000 a month. But I do get unlimited data including tethering, so that's pretty great.