I agree that the best is to know an algorithm for every outcome, but not everyone is there yet and many will never get there. I admire all who have learned 57 OLL and 21 PLL plus hundreds of more algorithms, amazing.
Today many records are very difficult to beat unless you have skips and luck. If you never solve the top layer in the way that can give you skips and luck after every set of algorithms you will have difficulties to beat a record, you will have hard time to get that jackpot because you don´t want to gamble.
This way might be slightly slower compared to someone who know full OLL and PLL, but this might also give a boost for those who don´t know full OLL and PLL.
Every methode to solve the LL have pros and cons. For HALL you need to locate the corners and do either single swap or double swap, thats it. It is pretty obvious after that what to do, you need to rotate the corners. You don´t need to learn a bunch of more algorithms, only learn more and more OLL till you feel comfortible.
HALL is not nessessary that bad for speed solving if you are on your way of learning all OLL and PLL.
This approach has few alg, the chance of making errors are few, you don´t need much planning except to know the corners after F2L. You have probabilities of skips and luck in every moment.
Question, can you solve the F2L faster and more efficently if only do that as easy as possible?
If yes, you save time. The LL can give you a nice setup without preparation.
If you don´t get that a good pattern, swap corners, when you do that you can solve the LL or get another OLL pattern that you can solve at once.
If you don´t get a good pattern now, use a Sune and you might solve the cube or get a new OLL pattern you can solve at once.
HALL is a gambling approach that is kind of error free and straight forward. I don´t think you will perform that bad with HALL if you don´t get a skip or luck with a pattern you can solve at once. But when you get a skips and luck with a pattern you can get a great result instead.
Maybe there are Cubers out there who like this kind of gambeling to reach better PB. It is up to everyone to find a trigger algorithm that suits different corner constalations so you by apply right trigger get all corner right with all colors right just by doing the trigger.
I think you need to gambeling to break new records today, you need to find ways that raise you luck to get skips and ways that reduces pattern you need for solving the cube at once.
Thank you for your professional view