I have PyroPlus but I mine with protection 4 armour anyway. I just wear it wherever I go in case a swarm of skeletons comes out of nowhere and shoots 20 arrows at me in one frame XD
dont see why you wouldnt. you cant stack ores in those item slots. just wear armor so youll never die to mobs.
Mobs are extremely rare in mining world, I have only seen a handful of them, so the prot4 is mainly for lava protection.
If you want fire protection, use "Fire Protection IV" armor instead of "Protection IV" armor, works better in lava. Protection IV is mainly for mobs. I wear max armor to make my character look cool while mining, not needed as I have pyro+, fly+, /back, multihome++.
Simply because I don't bother to spend money on that. I wear some random pieces to make my character look cool I do however have pyro+ and fly+ so I don't really need it either.
I do even though I have pyro plus. Because even though mobs are rare it is the one time your not wearing it that you look up into the eyes of a creeper.