does MacBook Pro need a DAC?

If money is an issue, you can get Audirvana for $79.00  It is a vast improvement on the built in DAC. 

Either i'm missing something here or need to point out an error.  Audirvana is a media player (software). It is not a hardware digital-to-analog converter.  If you use Audirvana (or itunes or any other player) you still need a DAC to physically create the analog wave-form from the code.  The MBP has a cheap one built in.  You can buy external, better ones from $100 -->> $10,000, with diminishing marginal returns.
Someone also asked about the superdrive.  In general any such removable, optical media, compared to playing the ripped file off the HDD or SSD (better) will generate higher noise at minimum. Whether you find this significant depends on many factors that i wont get into.

Coincedently, this weekend I received a used, Audioquest dragonfly, black that I bought for $50 on eBay.
It was a very noticeable improvement over my 2016 MacBook Pro's analog output. The mids and highs were much more clearly defined...making the Mac DAC seem quite muddy and distorted.
It's not as good as using the DAC in my Marantz cd6006, but it's portable...like my laptop.

Some MBP laptop's headphone jack (3.5mm) is also an optical output!  Really.
when sending audio out, look straight in to the empty jack... If you see a little red light inside, then it's a digital optical out that can connect to a optical input on a surround receiver or any device with an optical input.

Oh, hell yes...
 you. Definitely need a DAC for Mac Book Pro myself I’m replacing my PS Audio DAC III
with either a Schiit Audio Gungnir or if I can get my hands on Denafrips Ares II DAC
both are R2R DACs.

As many have stated a DAC will make for a significant improvement. Evan a simple USB driven one such as the Audioquest Dragon fly models or even a Schiit Modi 2.