Water is by nature a great solvent and RO water is even better. Since RO water has had pretty much everything but the H and O removed it will leach minerals and metals from anything it is exposed to.

RO faucets are usually lead-free and the quality ones are NSF certified. If you are intent in running RO water to another faucet contact the faucet manufacturer and ask them what the faucet is made of. Tell them you want to run RO water to it and see if they have any specific info.

I gave up on instant hot water dispensers after the first replacement. At one time I did have RO hooked up-can't remember the second time...but it could be why the second one started tasting so bad so soon. If you install an instant hot water heater I would stay away from RO supply. Now that I think about it the second time I had a simple inline filter hooked up. That may have removed enough minerals to cause leaching.

If you want RO with an instant hot water heater, just make sure that:

1) The tank is stainless steel
2) The faucet is low/no lead

There are many, many, many faucets that are fine and several tanks. One person's bad experience with inappropriate equipment is not a reason to stay away from RO supply to an instant hot. If done correctly, you will have NO issues whatsoever.

You are probably correct alice, a high end unit that will probably NOT be in Lowes would be OK.