The difference in hps between a d6 hps and a d10 hps is 2xlevel+2, so at 10th level the difference is 22hps. 26.5 hps from one false life, on top of the hps she already has at 10th level, will give the bladesinger more total hps than the 10th level Fighter or Paladin standing next to her. If she loses them in one fight she can cast that again between fights without a short rest and then a 3rd time after a short rest. On top of having more hps at the start of the fight, she is getting hit less and losing hps slower.Calling 20-30 THP “a ton of hps” is wild.
Play like you want. If you don't want to tank bladesingers that is cool. However, that is a self-imposed limitation due to build choices or thematic choices, not something supported by the mathematics and mechanics.