Touchwood but when something is wrong, the hospital bill cost tons, thats the worrying part which push me to thinking to opt for higher coverage...
You are correct to plan ahead. However, in such cases, opting Class B1 and below will enjoy Government subsidy (as for now unless policy changes).
If you think you can afford it, then it is a personal preference to go for it. My opinion is that when we are in our employable years, aka 21-65, we need the best kind of medical coverage to make us healthy so we can continue working to generate income. Thus staying in private hospital can sometimes speed up the treatment and make us well. With better care, our younger bodies can get back our health and hopeful go back to work and generate income. After we past that age 65, generally our liabilities are mostly gone ie. kids growth up and parrents maybe no around anymore.
We still NEED medical insurance, just that we given private or restructured may not make a big difference in our recovery namely because our body is weaker once older.
However, you can still choose for plans to cover for private if they is your preference because, you can always choose the kind of medical treatment you want. So i think it's about choice. Eating steak at hawker centre or hotel is really personal choice and affordability.
So you can still buy coverage for Private hospitalisation if thats want you really want and can afford the high premiums.
Anyway all plans under Medisave health insurance aka all the private integrated shield plans are all integrated.
Meaning, if affordability becomes an issue at old age, you can always reverse back to Medishield without the need to go through medical underwriting again.

So it is downgradable in a sense.