Negative.
They drive up the price of including UTXOs into transactions, thus rendering small UTXOs unspendable. This limits the amount of people that can participate in Bitcoin.

They put unnecessary data into parts of transactions, increasing the average size of each block, which puts pressure on node running costs. The higher node running costs, the less nodes, and thus less distribution.

They annoy the hell out of people by making transaction fee prices less predictable.

My own rant: they don't need the world's most damn secure network to be secured. Let BTC focus on what's actually important: sound money.