It’s not the same:
Freizügigkeitskonto in 2nd pillar is used when you are not currently connected to a Pensionskasse, either because you are unemployed or you are self employed. This is where your 2nd pillar money will be stored until you connect to a new Pensionskasse.
The big 3a for self-employed people that don’t have a 2nd pillar allows you to pay up to 20% of your income or max. CHF 33’840 into your 3a.
Some people are able to hide their Freizügigkeitskonto from the new Pensionskasse and keep it there. The law is clear on this: Your money has to go to the Pensionskasse, but might be worth a try. Not sure what the risk is.