The advantages are highly dependent on your personal financial situation. DO NOT try this based on reading a few APC posts. At a minimum, spend a couple hours on Bing/Google looking at Backdoor Roth and Mega Backdoor Roth. It is also worth a trip over to the lawyer version of APC https://www.biglawinvestor.com/. It is a forum where highly compensated professionals (lawyers) discuss investing and finances.

My primary purpose is for estate planning, not retirement planning. A Roth account does not have a required minimum distribution like a traditional account does, therefore it is one of the vehicles I'm using for estate transfer. A secondary purpose is for income splitting, so I can access retirement funds without increasing my taxable income via 401K withdrawals. I'm expecting a higher tax bracket in retirement, due to my "side hustle", therefore Roth is advantageous.

I set my deductions set to take 75% of pay into a 401a after tax account until my contribution plus the company 16% hits my 415C annual limit. Every pay cycle, I call Fidelity and move the money from the 401a, into my Roth IRA. It doesn't take long to hit the limit with a good PS check on 2/14. After the 415C limit, the company 16% is paid out as DPSP cash, since they can't contribute into my retirement account. At the point I've hit the 415C limits, I fund a Traditional IRA, convert it to a Roth(currently $5,500) and max out my HSA.

I've placed a high priority on Roth funds, so my approach is fairly aggressive. It also results in no take home pay for the first few months of the year. It can be done in a more balanced manner throughout the year with more of the company 16% flowing into the pretax portion of the 415C limit vs DPSP cash.

DYODD and get real advice from several other sources.