Well, I'd say there's a couple of things to think about.
One is tension. A lot of new players I see playing with their heels high have boatloads of tension in their calves and/or in their thighs and hips. They're holding their foot/leg high between strokes. This has upstream effects all the way to the lower back and can effect your overall mechanics in other limbs. So go ahead, play heel high but be careful that you're not unnecessarily holding tension in your leg that will slow you down, fatigue you or actually effect your other limbs' ability to operate. Tension in the leg can even lead to tension in the shoulders and arms. It's all connected.
Another thing to think about is stool height. I find that a lot of new players -- especially kids - who play with their heels high also tend to sit too high (and sometimes very low) and don't have a solid core when they play and are playing out of balance all the time. This becomes very noticeable once you try to get them to use their HH foot as well. They tend to lean on that leg for balance. So, I think there's a few things to be careful of in the beginning to make sure you don't have big problems later and end up going through the frustrating process of re-learning body mechanics just to be able to reliably open and close the hats.
The last thing to consider is control. Again, a lot of new players who play with their heel high are basically just stomping on the bass drum pedal. Their foot either loses or nearly loses contact with the pedal frequently when they play. They also find that when it comes to try and play quick successions of two or more notes later that they struggle because the entire motion they're using is being initiated by the thighs and hips which are big, cumbersome and ssssssllllllllooooooooooow as mollasses compared to smaller muscles lower down. This is particularly the case for new players who play heel high, stomp AND bury the beater.
So, in general, I find that encouraging a lower heel tends to help theses players release the beater, relieve tension, get better control and become more aware of their posture and mechanics.
But, truth be known, I start most of my students off playing heel down. They learn control and dynamics and the motion used to play heel down is applicable to more complex techniques playing heel up. More importantly, I find it helps them learn balance and body mechanics more reliably. They learn to stay rooted and not be floating around on their stools. I also do this as a sort of push back against the "kick drum" mentality in an attempt to get them thinking more about control and dynamics rather than just bashing the things into submission. But, that's me and I'm turning into a bitter old curmudgeon.