Why?
Romans 16:5
Greet also the church that meets at their house.
>>Go to mass.
>>Why?
This was in answer to a question, the question it was in answer to answers your question as far as the context of the question and the answer.
As for your verse, it concerns where - rather than why - and mass, the liturgy including the Holy Eucharist, was also held in homes in catacombs and elsewhere including ships and battlefields and prison camps.
If you are interested in other descriptions during the very early Chuch, you might look up the First Apology of St. Justin the Martyr.