That really depends on two things.

If you would rather pay income tax on those employer contributions this year or in some future year. Basically if you think you will be in a lower tax bracket now or later.

And if you think your income will ever be large enough that you will no longer be able to directly contribute to a Roth IRA and will want to use the "backdoor" method. (currently $140kish for single and $220kish for married) if you think you will use the backdoor someday, the existence of an old traditional IRA complicates things.