Freetrade are wise to advise all clients to use an ISA as it is a one size fits all safety net they cannot be criticised for. While it also makes them money it’s still a good value for most investors. However remember You can make:
capital gains of 11,700
Dividends of 2,000
Interest of 1,000 basic tax payer or 500 for higher rate tax payer
…without paying any tax. If you want you spend 36 quid a year that fine. Unlikely to make a big difference and helps supports the site of which I am an investor in.