Public or private channel

Many services like Strike and Zap use the Lightning Network. What I’m curious about is whether these companies use private or public channels when operating on the Lightning Network. For example, if I send a small amount of satoshis to John through the Strike app, would it use a private channel or a public channel?

I think, for user transactions, such as sending satoshis from one Strike user to another, public channels are typically used to ensure the transaction is routed efficiently and reliably through the Lightning Network. Private channels might be employed for specific, internal purposes but are less common for general user transactions.