This is bad in the short term for Bitcoin. Because Dell uses Coinbase(instead of accepting and keeping Bitcoin directly), coinbase will need to eventually sell the BTC to cover the USD they gave to Dell. This is why the price is dropping. Then people start to panic and sell as well.
In my opinion it's important for BTC to change hands, so in the long term this is good. Anyway I don't think a lot of companies if any big ones are keeping their profits in BTC, mainly because it could be worth less tomorrow that it is today. They still trust fiat more.