The term house church can be misleading. We tend to think of a church meeting in a house, but the translations that talk about churches are misleading - church was a later invention by people using Greek thinking. Still, structure can help, especially for those trying out the transition. For example when we agree to meet it does help if we agree a time and place (even if there's just two meeting). Mind you under oppressive regimes God can call the people together, thus reducing the risk. But questions like "what should we do" or "what do others do" can be limiting. On the other hand, without guidance, a group may flounder aimlessly for a while, before members eventually drift off from the group.

I was intending to say "a group of young Christians" in the previous sentence - but it is often those who were part of churches for years that often have the hardest job adapting to freedom. They are used to particular styles of prayer, music, clothes, speaking, etc. Suddenly the rules are out the window. Even the purpose of meeting will have changed - as will who will 'lead" - or speak - or sing ....

There are "house churches" where non-Christians come together to examine what the Bible says, and what it might mean for them. This is rare (and theologically calling a group of not-yet Christians a church is questionable), but one I'm thinking of one saw conversions of members one by one over time. They continued meeting as before - so presumably, then there's no issue now - and God was at work the whole time. Thus even the adoption of a term like house church can imply structure - hence some people preferring terms like simple or organic church.

People are individuals - with differing ideas, personalities, strengths, weaknesses. Groups of people combine all of those differences of their members in unique ways. There are often similarities in the way groups choose to operate - but "because we've always done it that way" is not a valid reason for doing something.