Super fair question. Frankly, it's unlikely to ever be a
big deal. Font design and choice is always a game of small details and your desire to spend time and effort on it depends on how much you care about small details.
For an art director doing print or web design, each and every single detail is vital. They are attempting to ship something as close to perfection as possible. From this grows a fantastic font market where artistic craftsmen have learned to honestly, subtly insert comfort, exoticism, 70s appeal, honesty, clarity, or any of many other subjective emotions into just a few pixels difference in the shape of letters we see all day every day.
But yeah, honestly, when coding, that stuff isn't going to kill you.
At the same time, there's a huge market of experts who have often released free monospaced fonts using the accumulated knowledge of the craft described above. It's easy to find fonts which solve the obvious problems (li1, oO0, mn) and possible to find ones that solve less obvious problems (textual color which can reduce reading stress, condensed fonts which can pack more into a line without feeling cluttered, larger x-height which can appear more inviting).
'Monospace, next question?' is really 60% of what these fonts can give you. 'Modern monospace, next question?' is probably 95%. The last 5 is just there if you care about it. Like usual, the last 5% is 500x the effort of 'Modern monospace, next question', though.
