I've toured using hotels, hostels, non-cooking lightweight camping and full cooking style camping over several months.
My non-cooking tours have been over 2 weeks and the cost of eating adds up, esp if you are in N Europe. You still need to carry food, eg picnic style bread, cheese, sausage and fruit and this can take up space.
It is hard to camp wild in many parts of Europe. Land is either urban or agricultural. Beach areas are patrolled at night , camping and open fires are forbidden.
Denmark has a network of free or very low cost primitive campsites that are really good. Scandinavia has wild-camping by right but the cost of food is very high.

Commercial campsites can be quite crowded in summer and a tarp offers little privacy. If you do go by tarp, try and get one where you can close the ends off.

Weather conditions vary from hot and dry in the S to temperate and occasionally rainy to unseasonaly cold with snow on the mountaintops.

If I was to go minimal camping on a race bike I would fit a clip-on rack and 2 small panniers or a large carradice saddlebag + barbag. Credit card touring with a credit card and small saddlebag is mostly a marketing myth.