Those companies only want to offer BTC as a payment option but don't want to hold crypto themselves. So they didn't really choose BTC to start with. Which makes sense since most companies need to pay their costs in fiat money.
It's the same thing as a US company wanting to sell to Europe but not wanting Euros, because they pay their costs in USD.
I think the point here is probably that Paypal is noticing that an increasing amount of consumers have crypto and would like to pay with them, so they offer this possibility.
Bitcoin is just another currency, and indeed most businesses don't want to hold them because they need to hold their local fiat. That doesn't mean consumers don't want to use Bitcoin tho.
