Does it affect us, though? We have 5K errors and 10K transactions in the free plan, which is sufficient for our use case. The $29/month Team plan includes 50K errors and 100K transactions.
If we set our on-demand cap to 0, in case something breaks and starts sending tons of requests (they still have spike protection, though), then it should be less than the cost of maintaining our instance.
If we are planning to use it for our Open edX instances, though, then indeed - self-hosting would be a much better option.