Well, I don't see it wrong if you want to monetize bitcoin as an exchange for your services. I believe it exist for it to be used as an exchange as an alternative. As long as you follow guidelines provided by your country regarding fares, taxes, and other services I think there's nothing wrong with that.
I fully support this opinion. This is your work, you are not a volunteer. You make seminars and trainings so in my opinion providing of monetization is right, but do not be greedy, make the price acceptable
The venue of the seminars are always be paid for before any training can take place. Monetization of the process is for the benefits of the attendees because, the trainer will be motivated to download all to the trainees. Nothing is more motivating than monetizing a process. Sometime ago I had to collect some payment before given out some first hand information.