Yes, “home altar” is a colloquial term and is harmless, if inaccurate. OTOH, the use of that term does, it seems to me, perpetuate a lack of appreciation of the mass being a sacrifice: sacrifices require an altar, prayer does not. There is a reason we have altars in our church buildings. That reason does not exist in our homes.
I can’t help but wonder if, in the old days when the mass was always referred to as a sacrifice, before the overuse if the word meal or banquet, came into being, people who had home prayer corners/oratories, ever used the term altar. I suspect not.