Isn't there something with VeriBlock spamming the mempool?
How many spams tx that they do? Are you saying those 400k comes from tx spam?
Truth to be told, daily transactions doesn't mean that much if the majority of those transactions comes from exchange/traders. No real usefulness there except speculation. Trading volume also rises to around 100k btc daily on a major exchange, maybe it's just a start of a trading wave.
I am quite sure that the majority of these transactions are coming from exchanges which really means that speculations are back in terms of volume. Of course, many can be saying that speculations in itself will not be helping Bitcoin and can even be hurting its future...but then again speculations can make Bitcoin get into the news again and can be encouraging more and more people to get back into the game. I am just hoping that we already learned the lessons in 2017 so we never commit the same mistakes again and again.