A company pays for work done in BTC. They want to put that into their books as an expense to reduce their tax burden. The other party that did the work is now on record and can be taxed also.
And it is taxed even if it's off record; not declaring the income and successfully keeping it off record doesn't mean "not taxable", it means "tax fraud".
If you manage to hide that income for some time but it comes to light a few years later - BAM, you owe the back taxes in triple+interest.
