M1 Finance already has fractional shares too. They're newer than Robinhood but they're built to be more of a long-term investing platform. Robinhood's UI feels more like a gambling platform to trade hourly on IMO. M1's "Pies" feature is very compelling. https://www.m1finance.com/how-it-works/invest/pies
(I do not work for either. I've used Robinhood for 4 years.)