It's use would be exactly in the fact that it's disposable. If a players shoots at it, it's only a 60 point unit. If a player ignores it, it's still a multi-melta. It can run interference, blocks lanes of travel and lines of sight. It's a mosquito.
If you're already writing it off as "disposable", my advice would be to invest the points into something else, preferably another unit (or two, or three) to make it stronger/more survivable/better.
Land Speeders (at least in my mind) are those units that if you ignore for too long, will always come back and bite you. If it were me playing against a single Land Speeder, I'd probably send at least 1 or 2 Missiles at it, just to keep it from shooting. While that does divert attention away from your other AV's, it isn't conceivably difficult to incapacitate it for the entire game. Which is why I would either A) Run at least 1-2 more Land Speeders, spreading them into 2-3 different units or B) don't use them at all.
It may be a 60 point diversion, but if you're only consuming 1 or 2 Missile Launchers from the enemy, is it really worth it?
Looking at your adjusted list, here're my other suggestions:
1. The Scouts are adding very little to your list. I would suggest taking a Devastator Squad instead. Granted, this would mean you having to lose one TFC though. However, for 230 points, you can have a squad of Devastators with 4 Missile Launchers. And if you Combat Squad them, that'll give you 2 squads with 2 ML's, hiding in 2 different terrain structures (which can still be Bolstered by the 2 other Techmarines manning your other TFC's).
2. If you decide to go that route, that'll leave you with 70 points, which would be ideal for another Land Speeder with MM/HF. Now your other "mosquito" has a partner in crime.
With this in mind, you now have 4 less TFC templates and 8 Sniper Shots, but have replaced it with 2 extra Missile launchers, and another Multi-Melta and/or Heavy Flamer. Your Anti-Tank is more reliable, both in strength and range, and (IMHO) have sacrificed very little of anything else for it. I understand this is taking a hit to your "flair", and I apologize if that's not what you're willing to give up on, but it's just my 2 cents. Hope you found it helpful.