1. It will make you smarter
Exercise is scientifically proven to stimulate your brain . You will meet many more people, come across tonnes of incredibly beautiful landscapes and cultures. This will fill your mind with lots of stimulating information.
2. It will make you fitter
Cycling 8 hours a day with a bicycle loaded with kit will make you fit.  Cycling is an excellent exercise, fantastic for cardio.
3. You will discover one of the most politically advanced areas on the planet
Europe is a relatively small area with a huge diversity of different countries with their own cultures, that co-exist in relative peace (since the last world war). What Europe has achieved has never happened before in the history of the world, and you can go and explore it.
4. It is safe
Europe, compared to some parts of the world, is a very progressed place with good safety record and lower levels of crime. There are many new long distance cycling routes that allow you to get off the road. The cycling culture in Europe is well progressed (think Tour de France, Amsterdam).
5. Its easy to get hold of spares and repairs
Bike culture is widespread in Europe and in most cities and towns you will find bicycle shops that stock modern bikes and Shimano components. If you have any problems with your bike, its likely you can hop on a bus and get to a bike shop quickly.
6. It is easy in terms of currency
The Euro means that you can travel around plenty of European countries and only need to carry the one currency which is convenient and saves money on conversions.
7. Europe is a great stepping stone to get used to life on the road
Combining all the benefits above, you can travel around Europe without any experience and enjoy yourself, but gain plenty of knowledge that will provide a foundation for travelling further afield to more adventurous places.
8. Plenty of people speak English in Europe
English is widely spoken in Europe so language is less of an issue.
9. There is a huge amount of variety in temperature, climate and geography
From the hot summer in Spain to the arctic circle in Norway, the plains in Hungry, the French Alps or Romania mountains, you have a huge amount of variety in Europe.
10. There are tonnes of travellers and a great travel network in Europe
The infrastructure is well advance for travellers. Public transport is generally very good, flights are cheap, people expect tourists but understand not to bug them.