I agree with many of the things that have been said except a few.
I agree that you should play hand exercises as well as playing single bass patterns on your left foot. For me. I find just hitting crashes consistently and together can be a challenge when I've gone so long doing it with right foot/right hand and then left hand right foot crashes.
Although I rarely have an opportunity to play double bass patterns on gigs, I do practice it and want to use it when I feel I have consistent enough playing that matches my single bass drum playing and - I have the right gig. I use a DW5002.
I wouldn't have said it in such a "black and white a fashion as "get rid of your double pedal and play some hi hat" but I do think drummers, especially beginning drummers,should understand how important left foot hi hat technique is for the overwhelming bulk of contemporary drumming, Metal or other aggressive rock styles have little place for these techniques as a foot chick is lost amongst stacks of Marshalls.
But so many other situations benefit from a consistent and musical hi hat approach using foot technique that neglecting it would be a mistake. You just don't know what your musical tastes will be like in 10-15 years.
I also feel uneasy about the "no pain, no gain" approach. Here's a quote from the late great Jim Chapin:
"If they tell you no pain no gain... shoot them." - Jim Chapin
Jim came from a different era but that era included guys like Buddy Rich and Louis Bellson. I don't like to use the word 'legendary' but Buddy's speed on hand and foot was just that. I doubt he or anyone of that generation would tell you to push through the pain. That just feels physically dangerous.
I'm not saying we shouldn't push ourselves. Going past a point of fatigue won't be as damaging as pushing through pain when it comes to technique.
I think 'cross training' is more beneficial. Steve Smith has a great way of doing this from History of the US beat:
With this technique you combine different muscles and techniques for a more comprehensive approach.
I know that metal drumming is more physical but I think I'd go the route of improving in a more healthy style. Heck, Tommy Aldridge has ridden bikes throughout his career to keep his fitness level up. The man can kick serious booty on double bass.