The ability to learn about algorithms from real world problems that are solved in production is amazing! I have learned so much by solving these interview questions, but it's also really fun because they're very challenging (and sometimes ridiculously hard).
It gives you an opportunity for your brainwork out of work hours which can be super helpful especially if working at home or remote during quarantine times like we all currently face right now with COVID-19 pandemic issues going around us daily!! There aren't many companies where learning through interviews works this well - definitely give them try. If there was anything i would change then maybe make more time available between each question/problem set up since some people may not get enough sleep due their job responsibilities as software engineers being self employed etc.. Definitely go ahead take advantage while its still free before prices increase after April 1st 2020 when pramps subscription will start costing.