Like most things there are pluses and minuses with a solo trip.
The minuses have been mentioned so I won't repeat them.
The pluses are that if you want to dedicate 100% of the time to golf you can do that, not waste time with leisurely meals, sleeping late because you stayed up all night etc.
Or, if you're the person who likes sleeping late, long meals, sightseeing and little time for golf you can do that too.
The more people on a trip, the more compromises on what to do, when, where to eat, where to stay or eat in terms of cost etc.
Depending on who your friends are, even though it costs a bit more to travel solo you more than make up for it by playing twice as much golf in the same number of days (or playing just as much but on a shorter trip.)
Your experience may vary.
Michael K Craig