Your markup/middleman argument pretends that Bitcoin didn't fairly recently have massive fees for transactions - for a while, one's $10/month Pornhub subscription would've cost $40+/month. (Side note: said monthly subscriptions are another challenge here for crypto and porn...)
Cryptocurrency stored on an exchange can be frozen, just like one's PayPal balance can be. Wikileaks takes PayPal (and credit card, bank transfer, checks, etc.) donations currently on their site.
Bitcoin's developers have refused for years to do what's necessary to avoid high fees like that. Luckily there are other cryptocurrencies, like Bitcoin Cash, which consistently have < 1 cent fees.
The infrastructure for automatic payments isn't there yet that's true. There's no reason why it can't be done though. I also have recurring payments for my email service, VPN, VPS and domains which I pay using cryptocurrencies.
To be fair the point of cryptocurrencies isn't to store them on an exchange (although you can) as some of the benefits are then lost.
That Wikileaks take other options doesn't retract from the point that there are clear benefits for them to accept cryptocurrencies.
Cryptocurrency stored on an exchange can be frozen, just like one's PayPal balance can be. Wikileaks takes PayPal (and credit card, bank transfer, checks, etc.) donations currently on their site.