Working on a training course and selling it on the web is a big job. It's not uncommon to sell it for 150, 200$ or more.
It's not a huge price to acquire new skills.
However, not all users are used to pay for that and 200$ can be a brake.
Offering payment flexibility to your customers can be a very good way to increase your conversions.
200$ in 5 months for exemple (40$ * 5) has a much smaller impact on a monthly budget.
I made a woocommerce plugin to add this feature.
To buy this plugin, you just have to go there there.
(Post on 2018-09-14)