It's not easy for Minehut to add paid plugins because the authors usually don't want their plugins to be on a server host because they would miss out on a loooot of sales so the chances of it being added aren't that high I'm sure pop will look into it tho.
They also have this line in their TOS
1 copy per server-network (connectable with the same IP) (or a server) and no more than 3 servers per plugin copy.
And do to Minehut being an entire network it exceeds the 3 server limit by a liiittle bit.