There are even some people using the Lightning Network, but that impact should have no impact now, because it is still negligible. ^hmmmmm^
No matter what the reason is, we are seeing 2MB Blocks and a reduction in the MemPool, which is good. ^smile^
when price is dropping it means people are selling their coins, then the panic beings and more people sell their coins. a large part of these sellers will be making transactions to move their coins to exchanges to sell. there are also a larger number of people buying because it is a dip and a considerable number of them withdraw => more and more transactions on chain.
in other words people who are saying less usage because price dropped are either misinformed or are spreading FUD.
regarding LN, the impact is not negligible, it is non-existent because there are practically no place that is accepting bitcoin through LN. any place major with any significant effect... it is more like a testing phase.
there are currently 134 LN nodes though and the network has been growing with a very nice speed.
regarding blocks, we have had 20 blocks bigger than 1.5 MB, 5 of which have been >=2
it is funny i made this Milestone topic 2 days ago and nobody was interested in it
https://bitcointalksearch.org/topic/2018-bitcoin-milestones-22-mb-block-and-81-ln-nodes-171-channels-2796578