meddling with entropy and using a physical source (anything except what your computer generates) should be considered an advanced topic which regular users should not try to perform without first educating themselves on how it is done correctly and are aware of possible biases and other issues that might be involved.
I'm not sure about that, it's well known that computer generated entropy is globally less safe than physical ones, where have you seen the opposite?
first of all my point is that people should never use a method that they may not understand the risk of. for instance using a coin may sound safe but what if the user who was using this method used a biased coin? or messed up entering the results and put more 1s than he should have? or what if he used a bad code that converted things wrong?....
secondly when you say "less safe" you should know that it does not mean "not safe". for example there has been millions of bitcoin keys used so far, i bet 99% of them are produced by a computer and an RNG. we only have rare cases where a shitty tool like blockchain.info wallet, etc led to losses due to bad RNG. the decent tools such as bitcoin core, electrum, and lots of others have never had such problems!