I believe this is the wrong question – and in a moment I will explain you why.
The right question to ask should be: “Is it a good idea to redirect WooCommerce customers to a custom thank you page?”. And the correct answer is: “No”.
Why you shouldn’t redirect to a custom thank you page
There are two main reasons for this.
Unless you’re an expert coder, redirecting to a custom thank you page (here’s a snippet to achieve WooCommerce redirection upon purchase by the way) will mean losing the order details summary.
In plain English, your custom thank you page will not display the WooCommerce order details. Unless you code this, of course.
Second, most tracking and reporting within WooCommerce, Google Analytics, and other WooCommerce integrations only work on the default thank you page. In plain English, if you redirect to a custom URL, the conversion will not be recorded into Google Analytics if you use the recommended WooCommerce Google Analytics plugin.
What should you do instead
The WooCommerce default thank you page can be customized via PHP (if you’re not a developer you can hire someone to do this for you).
In plain English, the thank you page can display conditional content based on the product/s purchased (for example, a banner, a survey, a specific download), you can remove or reposition default elements, you can add social share buttons or a lovely thank you note.
If you see what I mean, it’s better to keep the default thank you page and customize it, as opposed to redirect to a custom URL where you’d lose order details, tracking and create more confusion. In fact, to what page would you redirect if there were 2 different products with 2 different thank you pages in the order?