Welcome to the site! My player is also a 2021, and I can tell you that lots of D1 schools are actively recruiting rising sophomores right now (especially pitchers). We were at a big 15u tournament last week that had dozens of colleges scouting the games, including P5 and mid-level schools. So it is possible that this school is interested in you specifically since they emailed your coach. That being said, it is also true that many college "prospect camps" are money makers. You should ask your HS coach whether he thinks this school has legitimate interest in you or not.
If you want more bang for your buck, then a showcase is a better option because multiple schools see you at once. If you want to go to school in state (which helps with costs), then choose a reputable showcase in your state. Perfect Game showcases are always reputable, PBR (Prep Baseball Report) is a less expensive good alternative in some states, and there are many other good showcases as well. Some showcases are specifically for high academic schools: Head First and Showball come to mind.
All that being said, most people on this site will tell you not to attend any showcases or camps until "you have something to show." In other words, don't waste your time and money until your skills are good enough to show off to college coaches. That's good advice. If your skills are good enough, and your parents can afford this camp or a showcase without breaking the bank, then go for it.
Also keep in mind that most kids are recruited through their travel teams nowadays. If you aren't on a summer travel team that goes to the big tournaments to be seen by scouts, consider finding a different team for next year.