You don't need full alt... I thought the same when I was playing kantan and ignoring finishers. Once you get to 4* inner oni, after 2 inflammations of the carpal tunnel and with the 3rd tendonitis, you will start to regret it. I know because I did it and now I've been stuck for months trying to get used to full alt. It's almost impossible to 1h 200bpm maps. With full alt there is no stress at all and infinite potential and when I mean full alt, I mean with 4 fingers 2 in each hand. I know some people use full alt to refer to 2 fingers button-swapping style, instead of single-tapping a color with each finger (e.g. LX index does blue and RX index does red) but personally I'm not good with moving horizontally and I find it much harder than 4 fingers full alternate style so I wouldn't recommend it, though I do know some amazing players in top 100 who do 2 fingers full alt like that, I guess it depends on the person but if you're coming from std you will definitely find it more easy to get used to full alt with 4 than 2 since you're used to play that way already at least with 1 hand. You won't find anyone above #1000 playing with 1h maybe with some exception who does it with the arrow keys or a dedicated controller and they probably still can't play average-high bpm maps like 220 bpm or even lower.