Yea as you said I think it really depends on what your doing.
If your planning to invest smaller amounts and invest in and out of stocks ‘frequently’ at any time then the costs at HL can add up quickly.
Long term stocks or ETFs investing in a regular bases (at £1.50) or one off large investments the cost becomes more more reasonable. Freetrade is cheaper in a number of scenarios, just depends on your needs and trade offs