As realization is fast in this method, they also invest in short term fd/p2p Lending. There is also rewards on cc bill/gst payments. it builds repayment history and helps in getting good amount of line of credit in cheaper rate. There magin is lower but cycle is much faster. There is also chance to write off certain expenses.
It will also helps in making connections if you want to dig deeper into business. He just need to employ some people, whose salary cost can be easily recovered as turnover increases. Plus wholeseller/ distribution network in india is highly efficient. (If only logistics were efficient). For 1rs difference in small SKU they will order multiple trucks full from Delhi to Bombay and once reached in destination they will dispose off in half a day.
Most people who do these things don't do it smartly. They cant see big picture, reselling few phones all they can think of. This is where proper education/ contacts helps a lot. Like the case of
@Divas_Garg.