Serious question, why would you not? It's designed to be incredibly convenient and the trades are zero commission. Why not use Robinhood to buy and hold, if you're just making simple plays (buying ETFs etc) and don't need high performance (ie executed immediately etc) trades?
My gut feeling is that RH is designed to maximize the number of trades people make, as a core "engagement" metric. A few examples: 1) The UI is designed to induce in the user the feeling that something is happening, always - the graphs are not to scale, so small swings in price appear bigger than they really are. 2) The "Top 10" and community trends feed will trigger FOMO, and again will likely result in more day-trading.
In all, RH has too much "clutter" and noisy notifications for a buy and hold investor. Most platforms are now commission-free.