Not really. This is just another gimmick like the 2% cashback but stiffing you with higher mortgage rates long term, which costs you thousands more than any bonus here.
You earn 1.35% interest regular saver, which is limited to 15K. You then get 10% of highest regular saver balance + any initial lump sum up to 20K, so largest bonus is 3.5K, as far as I can tell.
Your lump sum is getting a whopping .25% interest while dwindling away too.
All in all IMO this is just another trick product to fool customers into thinking they are getting a good deal