This is not true, the volatility of cryptocurrencies can be an issue for all of those people that are holding their coins for the long term and for all of those that are looking to obtain profits as a trader but if you want to accept bitcoin as a way of payment in your store there are services that convert your bitcoin to fiat immediately after you receive your transaction so you are only exposed to the volatility of the market for a few seconds.

So unless there is a crash in the market during the few seconds in which a big purchase is being done in your website then you have nothing to fear about the volatility in the market of cryptocurrencies.