I have used something similar in the past to patch up splits in aluminium panels. It worked but the filler material does not age in the same way as aluminium. Initially it looks bright and blends with the Aluminium, but over time the filler looks more like lead solder.
Amazing the amount of rubbish Youtube videos about this. Anyway, here is one I like. This bloke tins the parts to be joined. Brazing is always going to be best for lap joints. I always use a stainless steel brush to remove oxide layer on aluminium, and I use it for nothing else.
That's how it's done, not the enormous lumps that looked like peanut butter - less is definitely more!! Another trick I've read about is a carbon rich flame to blacken the aluminium first because it burns of at 400 degrees to let you know the temperature and you're good to go
The main use in the bike world is when attatching machined fittings - eg a threaded boss - into a light gauge tank. Where the sections of the pieces are very different - machined lump vs thin sheet - it's easier to do without a meltdown. You would not use it for structural joints. Bradley covers it very well in Vol 2 of The Racing Motorcycle. My copy now looks to be on permanent bloody loan I've never had to use it as I have a very good TIG welder locally.
Mine is in the hands of a guy called Neil Hintze who builds motors from scratch. He also developed a transfer port injected 2 stroke - went public with it and KTM copied it. They then tried to patent it..... The rolling chassis for my twin came from him - free. I must do a road trip one day to see him and ask nicely for the book back.
