Better question is: Is there anything a yanagiba can do that a suji can't do as well?
And for anyone not actively fabricating sashimi, the answer is a resounding no.
In your post you don't mention if you've bought or own a yani - if not, suggest you continue to use your suji, become more familiar with it's strengths and limitations, determine if you need or want a dedicated slicer and assess the suitability of your suji for your requirements.
A suji is considerably more versatile than a yani. Can be used to portion and/or slice all manner of proteins, sushi rolls, sub for a gyuto in a pinch. I like a 240 for a lot of home work, 270 for work, 210 for charcuterie or picnics.