iPhone SE Locked Vs. Unlocked for GAIA GPS?

I am considering buying a new iPhone SE for GPS hiking and biking, w/o a cellular contract.  Amazon sells them new, unlocked (SIM-Free) or locked to, say, AT&T.  The locked versions are cheaper.  Would either version work for GPS apps like GAIA?  I do not plan to buy a cellular contract.

Aside from my question above, is there any other reason to prefer a locked or unlocked iPhone if I am not planning to buy a cellular contract?  Would they work equally well for GPS chip and wifi use?