1) Houser has only one year of control remaining. Otherwise, he would've been a FA this offseason, in which case we wouldn't have gotten anything for him...
2) I don't quite know what you're talking about with Taylor having more value than Houser. This shows the opposite....https://www.baseballtradevalues.com/trade-simulator
3) It's still value and is even more valuable to a small market franchise such as the Brewers that cannot afford to spend tens of millions on mediocre starters like many teams did this winter in FA. You should look up the story of Junior Caminero. Rays ended up getting a top 5 prospect in all of baseball for someone with "miniscule value". Not that the Brewers pulled off something similar with Coleman Crow or are likely to if/when they trade Gasser, but you still don't just sacrifice value because a guy isn't a Burnes or a Woodruff.
4) Finally, filling innings for two weeks while Gasser is in AAA is pretty straightforward actually: Peralta, Miley, Junis, Hall, Rea, Ross....