If you spend 40 hours on this and it only gains you a 1% increase in salary then you earn that back in 2 years. I would say that it will generally earn you much more so personally I see it as a good investment. If you enjoy the take home you're also more likely to enjoy the role so it's also a filter for you. If you're not enjoying the take home then stop, but if you're finding it interesting then it's well worth it. These things are also for you to assess future Jon opportunities. The best take homes are as close to actual work as possible for a reason.