What's the point of the float in the swimming pool in Finland?

On Wednesday my friend and i went to the swimming pool in the city center. We just wanted to learn and experience something new or interesting because someone told me there is some water exercise.
At the beginning, we just practiced as all of us were not good at swimming even we live in a city with a lot of lakes and rivers. After swimming about 1 hour i still didn't learn the keys to swim very well and always stopped before the zone that was deeper than 1.5 meters.Then i wanted to use float that could help me swim easily. After i armed myself and was ready to swam again, the worker in the swimming pool came to me and explained that the float was dangerous for me as i was not good at swimming, if the float was loose when i went to deep zone, i maybe drown. 
I understand her point and i know her kind heart is  to keep me safe but i was still surprised and puzzled about the Finland security concepts. As in my country, only the learners or people who are not good at swimming use the float to avoid drowning . Why only people having  good abilities can use extra help tools while the starters can't. I'm even interested about how Finnish people learn to swim if they don't use float or other helpful tools. I also wonder what's the point of float if all the people know how to swim and are good at swimming. If they have already know their float is not safe why don't they improve this product and make float can be used for learners? Maybe it's because most of them are good at learning everything like skating cool as if they have natural talent. How cool they are, i really think Finland is a magic place.