Christmas tree light bulbs are connected in parallel, not series. can you think of a practical reason for this?

I think this is because in a parallel connection, any failure in one bulb doesn't affect the other bulbs unlike in series connection where a failure in one bulb will affect all the other bulbs in the circuit. This is because in a parallel connection bulbs they are independent, that is each bulb has a voltage which is the same for all the bulbs.